README.os2 revision 1.26
1If you read this file _as_is_, just ignore the funny characters you 2see. It is written in the POD format (see perlpod manpage) which is 3specially designed to be readable as is. 4 5=head1 NAME 6 7perlos2 - Perl under OS/2, DOS, Win0.3*, Win0.95 and WinNT. 8 9=head1 SYNOPSIS 10 11One can read this document in the following formats: 12 13 man perlos2 14 view perl perlos2 15 explorer perlos2.html 16 info perlos2 17 18to list some (not all may be available simultaneously), or it may 19be read I<as is>: either as F<README.os2>, or F<pod/perlos2.pod>. 20 21To read the F<.INF> version of documentation (B<very> recommended) 22outside of OS/2, one needs an IBM's reader (may be available on IBM 23ftp sites (?) (URL anyone?)) or shipped with PC DOS 7.0 and IBM's 24Visual Age C++ 3.5. 25 26A copy of a Win* viewer is contained in the "Just add OS/2 Warp" package 27 28 ftp://ftp.software.ibm.com/ps/products/os2/tools/jaow/jaow.zip 29 30in F<?:\JUST_ADD\view.exe>. This gives one an access to EMX's 31F<.INF> docs as well (text form is available in F</emx/doc> in 32EMX's distribution). There is also a different viewer named xview. 33 34Note that if you have F<lynx.exe> or F<netscape.exe> installed, you can follow WWW links 35from this document in F<.INF> format. If you have EMX docs installed 36correctly, you can follow library links (you need to have C<view emxbook> 37working by setting C<EMXBOOK> environment variable as it is described 38in EMX docs). 39 40=cut 41 42Contents (This may be a little bit obsolete) 43 44 perlos2 - Perl under OS/2, DOS, Win0.3*, Win0.95 and WinNT. 45 46 NAME 47 SYNOPSIS 48 DESCRIPTION 49 - Target 50 - Other OSes 51 - Prerequisites 52 - Starting Perl programs under OS/2 (and DOS and...) 53 - Starting OS/2 (and DOS) programs under Perl 54 Frequently asked questions 55 - "It does not work" 56 - I cannot run external programs 57 - I cannot embed perl into my program, or use perl.dll from my 58 - `` and pipe-open do not work under DOS. 59 - Cannot start find.exe "pattern" file 60 INSTALLATION 61 - Automatic binary installation 62 - Manual binary installation 63 - Warning 64 Accessing documentation 65 - OS/2 .INF file 66 - Plain text 67 - Manpages 68 - HTML 69 - GNU info files 70 - PDF files 71 - LaTeX docs 72 BUILD 73 - The short story 74 - Prerequisites 75 - Getting perl source 76 - Application of the patches 77 - Hand-editing 78 - Making 79 - Testing 80 - Installing the built perl 81 - a.out-style build 82 Build FAQ 83 - Some / became \ in pdksh. 84 - 'errno' - unresolved external 85 - Problems with tr or sed 86 - Some problem (forget which ;-) 87 - Library ... not found 88 - Segfault in make 89 - op/sprintf test failure 90 Specific (mis)features of OS/2 port 91 - setpriority, getpriority 92 - system() 93 - extproc on the first line 94 - Additional modules: 95 - Prebuilt methods: 96 - Prebuilt variables: 97 - Misfeatures 98 - Modifications 99 - Identifying DLLs 100 - Centralized management of resources 101 Perl flavors 102 - perl.exe 103 - perl_.exe 104 - perl__.exe 105 - perl___.exe 106 - Why strange names? 107 - Why dynamic linking? 108 - Why chimera build? 109 ENVIRONMENT 110 - PERLLIB_PREFIX 111 - PERL_BADLANG 112 - PERL_BADFREE 113 - PERL_SH_DIR 114 - USE_PERL_FLOCK 115 - TMP or TEMP 116 Evolution 117 - Text-mode filehandles 118 - Priorities 119 - DLL name mangling: pre 5.6.2 120 - DLL name mangling: 5.6.2 and beyond 121 - DLL forwarder generation 122 - Threading 123 - Calls to external programs 124 - Memory allocation 125 - Threads 126 BUGS 127 AUTHOR 128 SEE ALSO 129 130=head1 DESCRIPTION 131 132=head2 Target 133 134The target is to make OS/2 one of the best supported platform for 135using/building/developing Perl and I<Perl applications>, as well as 136make Perl the best language to use under OS/2. The secondary target is 137to try to make this work under DOS and Win* as well (but not B<too> hard). 138 139The current state is quite close to this target. Known limitations: 140 141=over 5 142 143=item * 144 145Some *nix programs use fork() a lot; with the mostly useful flavors of 146perl for OS/2 (there are several built simultaneously) this is 147supported; but some flavors do not support this (e.g., when Perl is 148called from inside REXX). Using fork() after 149I<use>ing dynamically loading extensions would not work with I<very> old 150versions of EMX. 151 152=item * 153 154You need a separate perl executable F<perl__.exe> (see L</perl__.exe>) 155if you want to use PM code in your application (as Perl/Tk or OpenGL 156Perl modules do) without having a text-mode window present. 157 158While using the standard F<perl.exe> from a text-mode window is possible 159too, I have seen cases when this causes degradation of the system stability. 160Using F<perl__.exe> avoids such a degradation. 161 162=item * 163 164There is no simple way to access WPS objects. The only way I know 165is via C<OS2::REXX> and C<SOM> extensions (see L<OS2::REXX>, L<SOM>). 166However, we do not have access to 167convenience methods of Object-REXX. (Is it possible at all? I know 168of no Object-REXX API.) The C<SOM> extension (currently in alpha-text) 169may eventually remove this shortcoming; however, due to the fact that 170DII is not supported by the C<SOM> module, using C<SOM> is not as 171convenient as one would like it. 172 173=back 174 175Please keep this list up-to-date by informing me about other items. 176 177=head2 Other OSes 178 179Since OS/2 port of perl uses a remarkable EMX environment, it can 180run (and build extensions, and - possibly - be built itself) under any 181environment which can run EMX. The current list is DOS, 182DOS-inside-OS/2, Win0.3*, Win0.95 and WinNT. Out of many perl flavors, 183only one works, see L</"F<perl_.exe>">. 184 185Note that not all features of Perl are available under these 186environments. This depends on the features the I<extender> - most 187probably RSX - decided to implement. 188 189Cf. L</Prerequisites>. 190 191=head2 Prerequisites 192 193=over 6 194 195=item EMX 196 197EMX runtime is required (may be substituted by RSX). Note that 198it is possible to make F<perl_.exe> to run under DOS without any 199external support by binding F<emx.exe>/F<rsx.exe> to it, see C<emxbind>. Note 200that under DOS for best results one should use RSX runtime, which 201has much more functions working (like C<fork>, C<popen> and so on). In 202fact RSX is required if there is no VCPI present. Note the 203RSX requires DPMI. Many implementations of DPMI are known to be very 204buggy, beware! 205 206Only the latest runtime is supported, currently C<0.9d fix 03>. Perl may run 207under earlier versions of EMX, but this is not tested. 208 209One can get different parts of EMX from, say 210 211 ftp://crydee.sai.msu.ru/pub/comp/os/os2/leo/gnu/emx+gcc/ 212 http://hobbes.nmsu.edu/h-browse.php?dir=/pub/os2/dev/emx/v0.9d/ 213 214The runtime component should have the name F<emxrt.zip>. 215 216B<NOTE>. When using F<emx.exe>/F<rsx.exe>, it is enough to have them on your path. One 217does not need to specify them explicitly (though this 218 219 emx perl_.exe -de 0 220 221will work as well.) 222 223=item RSX 224 225To run Perl on DPMI platforms one needs RSX runtime. This is 226needed under DOS-inside-OS/2, Win0.3*, Win0.95 and WinNT (see 227L</"Other OSes">). RSX would not work with VCPI 228only, as EMX would, it requires DMPI. 229 230Having RSX and the latest F<sh.exe> one gets a fully functional 231B<*nix>-ish environment under DOS, say, C<fork>, C<``> and 232pipe-C<open> work. In fact, MakeMaker works (for static build), so one 233can have Perl development environment under DOS. 234 235One can get RSX from, say 236 237 http://cd.textfiles.com/hobbesos29804/disk1/EMX09C/ 238 ftp://crydee.sai.msu.ru/pub/comp/os/os2/leo/gnu/emx+gcc/contrib/ 239 240Contact the author on C<rainer@mathematik.uni-bielefeld.de>. 241 242The latest F<sh.exe> with DOS hooks is available in 243 244 http://www.ilyaz.org/software/os2/ 245 246as F<sh_dos.zip> or under similar names starting with C<sh>, C<pdksh> etc. 247 248=item HPFS 249 250Perl does not care about file systems, but the perl library contains 251many files with long names, so to install it intact one needs a file 252system which supports long file names. 253 254Note that if you do not plan to build the perl itself, it may be 255possible to fool EMX to truncate file names. This is not supported, 256read EMX docs to see how to do it. 257 258=item pdksh 259 260To start external programs with complicated command lines (like with 261pipes in between, and/or quoting of arguments), Perl uses an external 262shell. With EMX port such shell should be named F<sh.exe>, and located 263either in the wired-in-during-compile locations (usually F<F:/bin>), 264or in configurable location (see L</"C<PERL_SH_DIR>">). 265 266For best results use EMX pdksh. The standard binary (5.2.14 or later) runs 267under DOS (with L</RSX>) as well, see 268 269 http://www.ilyaz.org/software/os2/ 270 271=back 272 273=head2 Starting Perl programs under OS/2 (and DOS and...) 274 275Start your Perl program F<foo.pl> with arguments C<arg1 arg2 arg3> the 276same way as on any other platform, by 277 278 perl foo.pl arg1 arg2 arg3 279 280If you want to specify perl options C<-my_opts> to the perl itself (as 281opposed to your program), use 282 283 perl -my_opts foo.pl arg1 arg2 arg3 284 285Alternately, if you use OS/2-ish shell, like CMD or 4os2, put 286the following at the start of your perl script: 287 288 extproc perl -S -my_opts 289 290rename your program to F<foo.cmd>, and start it by typing 291 292 foo arg1 arg2 arg3 293 294Note that because of stupid OS/2 limitations the full path of the perl 295script is not available when you use C<extproc>, thus you are forced to 296use C<-S> perl switch, and your script should be on the C<PATH>. As a plus 297side, if you know a full path to your script, you may still start it 298with 299 300 perl ../../blah/foo.cmd arg1 arg2 arg3 301 302(note that the argument C<-my_opts> is taken care of by the C<extproc> line 303in your script, see L<C<extproc> on the first line>). 304 305To understand what the above I<magic> does, read perl docs about C<-S> 306switch - see L<perlrun>, and cmdref about C<extproc>: 307 308 view perl perlrun 309 man perlrun 310 view cmdref extproc 311 help extproc 312 313or whatever method you prefer. 314 315There are also endless possibilities to use I<executable extensions> of 3164os2, I<associations> of WPS and so on... However, if you use 317*nixish shell (like F<sh.exe> supplied in the binary distribution), 318you need to follow the syntax specified in L<perlrun/"Command Switches">. 319 320Note that B<-S> switch supports scripts with additional extensions 321F<.cmd>, F<.btm>, F<.bat>, F<.pl> as well. 322 323=head2 Starting OS/2 (and DOS) programs under Perl 324 325This is what system() (see L<perlfunc/system>), C<``> (see 326L<perlop/"I/O Operators">), and I<open pipe> (see L<perlfunc/open>) 327are for. (Avoid exec() (see L<perlfunc/exec>) unless you know what you 328do). 329 330Note however that to use some of these operators you need to have a 331sh-syntax shell installed (see L</"Pdksh">, 332L</"Frequently asked questions">), and perl should be able to find it 333(see L</"C<PERL_SH_DIR>">). 334 335The cases when the shell is used are: 336 337=over 338 339=item 1 340 341One-argument system() (see L<perlfunc/system>), exec() (see L<perlfunc/exec>) 342with redirection or shell meta-characters; 343 344=item 2 345 346Pipe-open (see L<perlfunc/open>) with the command which contains redirection 347or shell meta-characters; 348 349=item 3 350 351Backticks C<``> (see L<perlop/"I/O Operators">) with the command which contains 352redirection or shell meta-characters; 353 354=item 4 355 356If the executable called by system()/exec()/pipe-open()/C<``> is a script 357with the "magic" C<#!> line or C<extproc> line which specifies shell; 358 359=item 5 360 361If the executable called by system()/exec()/pipe-open()/C<``> is a script 362without "magic" line, and C<$ENV{EXECSHELL}> is set to shell; 363 364=item 6 365 366If the executable called by system()/exec()/pipe-open()/C<``> is not 367found (is not this remark obsolete?); 368 369=item 7 370 371For globbing (see L<perlfunc/glob>, L<perlop/"I/O Operators">) 372(obsolete? Perl uses builtin globbing nowadays...). 373 374=back 375 376For the sake of speed for a common case, in the above algorithms 377backslashes in the command name are not considered as shell metacharacters. 378 379Perl starts scripts which begin with cookies 380C<extproc> or C<#!> directly, without an intervention of shell. Perl uses the 381same algorithm to find the executable as F<pdksh>: if the path 382on C<#!> line does not work, and contains C</>, then the directory 383part of the executable is ignored, and the executable 384is searched in F<.> and on C<PATH>. To find arguments for these scripts 385Perl uses a different algorithm than F<pdksh>: up to 3 arguments are 386recognized, and trailing whitespace is stripped. 387 388If a script 389does not contain such a cooky, then to avoid calling F<sh.exe>, Perl uses 390the same algorithm as F<pdksh>: if C<$ENV{EXECSHELL}> is set, the 391script is given as the first argument to this command, if not set, then 392C<$ENV{COMSPEC} /c> is used (or a hardwired guess if C<$ENV{COMSPEC}> is 393not set). 394 395When starting scripts directly, Perl uses exactly the same algorithm as for 396the search of script given by B<-S> command-line option: it will look in 397the current directory, then on components of C<$ENV{PATH}> using the 398following order of appended extensions: no extension, F<.cmd>, F<.btm>, 399F<.bat>, F<.pl>. 400 401Note that Perl will start to look for scripts only if OS/2 cannot start the 402specified application, thus C<system 'blah'> will not look for a script if 403there is an executable file F<blah.exe> I<anywhere> on C<PATH>. In 404other words, C<PATH> is essentially searched twice: once by the OS for 405an executable, then by Perl for scripts. 406 407Note also that executable files on OS/2 can have an arbitrary extension, but 408F<.exe> will be automatically appended if no dot is present in the name. The 409workaround is as simple as that: since F<blah.> and F<blah> denote the same 410file (at list on FAT and HPFS file systems), to start an executable residing in 411file F<n:/bin/blah> (no extension) give an argument C<n:/bin/blah.> (dot 412appended) to system(). 413 414Perl will start PM programs from VIO (=text-mode) Perl process in a 415separate PM session; 416the opposite is not true: when you start a non-PM program from a PM 417Perl process, Perl would not run it in a separate session. If a separate 418session is desired, either ensure 419that shell will be used, as in C<system 'cmd /c myprog'>, or start it using 420optional arguments to system() documented in C<OS2::Process> module. This 421is considered to be a feature. 422 423=head1 Frequently asked questions 424 425=head2 "It does not work" 426 427Perl binary distributions come with a F<testperl.cmd> script which tries 428to detect common problems with misconfigured installations. There is a 429pretty large chance it will discover which step of the installation you 430managed to goof. C<;-)> 431 432=head2 I cannot run external programs 433 434=over 4 435 436=item * 437 438Did you run your programs with C<-w> switch? See 439L<Starting OSE<sol>2 (and DOS) programs under Perl>. 440 441=item * 442 443Do you try to run I<internal> shell commands, like C<`copy a b`> 444(internal for F<cmd.exe>), or C<`glob a*b`> (internal for ksh)? You 445need to specify your shell explicitly, like C<`cmd /c copy a b`>, 446since Perl cannot deduce which commands are internal to your shell. 447 448=back 449 450=head2 I cannot embed perl into my program, or use F<perl.dll> from my 451program. 452 453=over 4 454 455=item Is your program EMX-compiled with C<-Zmt -Zcrtdll>? 456 457Well, nowadays Perl DLL should be usable from a differently compiled 458program too... If you can run Perl code from REXX scripts (see 459L<OS2::REXX>), then there are some other aspect of interaction which 460are overlooked by the current hackish code to support 461differently-compiled principal programs. 462 463If everything else fails, you need to build a stand-alone DLL for 464perl. Contact me, I did it once. Sockets would not work, as a lot of 465other stuff. 466 467=item Did you use L<ExtUtils::Embed>? 468 469Some time ago I had reports it does not work. Nowadays it is checked 470in the Perl test suite, so grep F<./t> subdirectory of the build tree 471(as well as F<*.t> files in the F<./lib> subdirectory) to find how it 472should be done "correctly". 473 474=back 475 476=head2 C<``> and pipe-C<open> do not work under DOS. 477 478This may a variant of just L</"I cannot run external programs">, or a 479deeper problem. Basically: you I<need> RSX (see L</Prerequisites>) 480for these commands to work, and you may need a port of F<sh.exe> which 481understands command arguments. One of such ports is listed in 482L</Prerequisites> under RSX. Do not forget to set variable 483L</"C<PERL_SH_DIR>"> as well. 484 485DPMI is required for RSX. 486 487=head2 Cannot start C<find.exe "pattern" file> 488 489The whole idea of the "standard C API to start applications" is that 490the forms C<foo> and C<"foo"> of program arguments are completely 491interchangeable. F<find> breaks this paradigm; 492 493 find "pattern" file 494 find pattern file 495 496are not equivalent; F<find> cannot be started directly using the above 497API. One needs a way to surround the doublequotes in some other 498quoting construction, necessarily having an extra non-Unixish shell in 499between. 500 501Use one of 502 503 system 'cmd', '/c', 'find "pattern" file'; 504 `cmd /c 'find "pattern" file'` 505 506This would start F<find.exe> via F<cmd.exe> via C<sh.exe> via 507C<perl.exe>, but this is a price to pay if you want to use 508non-conforming program. 509 510=head1 INSTALLATION 511 512=head2 Automatic binary installation 513 514The most convenient way of installing a binary distribution of perl is via perl installer 515F<install.exe>. Just follow the instructions, and 99% of the 516installation blues would go away. 517 518Note however, that you need to have F<unzip.exe> on your path, and 519EMX environment I<running>. The latter means that if you just 520installed EMX, and made all the needed changes to F<Config.sys>, 521you may need to reboot in between. Check EMX runtime by running 522 523 emxrev 524 525Binary installer also creates a folder on your desktop with some useful 526objects. If you need to change some aspects of the work of the binary 527installer, feel free to edit the file F<Perl.pkg>. This may be useful 528e.g., if you need to run the installer many times and do not want to 529make many interactive changes in the GUI. 530 531B<Things not taken care of by automatic binary installation:> 532 533=over 15 534 535=item C<PERL_BADLANG> 536 537may be needed if you change your codepage I<after> perl installation, 538and the new value is not supported by EMX. See L</"C<PERL_BADLANG>">. 539 540=item C<PERL_BADFREE> 541 542see L</"C<PERL_BADFREE>">. 543 544=item F<Config.pm> 545 546This file resides somewhere deep in the location you installed your 547perl library, find it out by 548 549 perl -MConfig -le "print $INC{'Config.pm'}" 550 551While most important values in this file I<are> updated by the binary 552installer, some of them may need to be hand-edited. I know no such 553data, please keep me informed if you find one. Moreover, manual 554changes to the installed version may need to be accompanied by an edit 555of this file. 556 557=back 558 559B<NOTE>. Because of a typo the binary installer of 5.00305 560would install a variable C<PERL_SHPATH> into F<Config.sys>. Please 561remove this variable and put L</C<PERL_SH_DIR>> instead. 562 563=head2 Manual binary installation 564 565As of version 5.00305, OS/2 perl binary distribution comes split 566into 11 components. Unfortunately, to enable configurable binary 567installation, the file paths in the zip files are not absolute, but 568relative to some directory. 569 570Note that the extraction with the stored paths is still necessary 571(default with unzip, specify C<-d> to pkunzip). However, you 572need to know where to extract the files. You need also to manually 573change entries in F<Config.sys> to reflect where did you put the 574files. Note that if you have some primitive unzipper (like 575C<pkunzip>), you may get a lot of warnings/errors during 576unzipping. Upgrade to C<(w)unzip>. 577 578Below is the sample of what to do to reproduce the configuration on my 579machine. In F<VIEW.EXE> you can press C<Ctrl-Insert> now, and 580cut-and-paste from the resulting file - created in the directory you 581started F<VIEW.EXE> from. 582 583For each component, we mention environment variables related to each 584installation directory. Either choose directories to match your 585values of the variables, or create/append-to variables to take into 586account the directories. 587 588=over 3 589 590=item Perl VIO and PM executables (dynamically linked) 591 592 unzip perl_exc.zip *.exe *.ico -d f:/emx.add/bin 593 unzip perl_exc.zip *.dll -d f:/emx.add/dll 594 595(have the directories with C<*.exe> on PATH, and C<*.dll> on 596LIBPATH); 597 598=item Perl_ VIO executable (statically linked) 599 600 unzip perl_aou.zip -d f:/emx.add/bin 601 602(have the directory on PATH); 603 604=item Executables for Perl utilities 605 606 unzip perl_utl.zip -d f:/emx.add/bin 607 608(have the directory on PATH); 609 610=item Main Perl library 611 612 unzip perl_mlb.zip -d f:/perllib/lib 613 614If this directory is exactly the same as the prefix which was compiled 615into F<perl.exe>, you do not need to change 616anything. However, for perl to find the library if you use a different 617path, you need to 618C<set PERLLIB_PREFIX> in F<Config.sys>, see L</"C<PERLLIB_PREFIX>">. 619 620=item Additional Perl modules 621 622 unzip perl_ste.zip -d f:/perllib/lib/site_perl/5.30.3/ 623 624Same remark as above applies. Additionally, if this directory is not 625one of directories on @INC (and @INC is influenced by C<PERLLIB_PREFIX>), you 626need to put this 627directory and subdirectory F<./os2> in C<PERLLIB> or C<PERL5LIB> 628variable. Do not use C<PERL5LIB> unless you have it set already. See 629L<perl/"ENVIRONMENT">. 630 631B<[Check whether this extraction directory is still applicable with 632the new directory structure layout!]> 633 634=item Tools to compile Perl modules 635 636 unzip perl_blb.zip -d f:/perllib/lib 637 638Same remark as for F<perl_ste.zip>. 639 640=item Manpages for Perl and utilities 641 642 unzip perl_man.zip -d f:/perllib/man 643 644This directory should better be on C<MANPATH>. You need to have a 645working F<man> to access these files. 646 647=item Manpages for Perl modules 648 649 unzip perl_mam.zip -d f:/perllib/man 650 651This directory should better be on C<MANPATH>. You need to have a 652working man to access these files. 653 654=item Source for Perl documentation 655 656 unzip perl_pod.zip -d f:/perllib/lib 657 658This is used by the C<perldoc> program (see L<perldoc>), and may be used to 659generate HTML documentation usable by WWW browsers, and 660documentation in zillions of other formats: C<info>, C<LaTeX>, 661C<Acrobat>, C<FrameMaker> and so on. [Use programs such as 662F<pod2latex> etc.] 663 664=item Perl manual in F<.INF> format 665 666 unzip perl_inf.zip -d d:/os2/book 667 668This directory should better be on C<BOOKSHELF>. 669 670=item Pdksh 671 672 unzip perl_sh.zip -d f:/bin 673 674This is used by perl to run external commands which explicitly 675require shell, like the commands using I<redirection> and I<shell 676metacharacters>. It is also used instead of explicit F</bin/sh>. 677 678Set C<PERL_SH_DIR> (see L</"C<PERL_SH_DIR>">) if you move F<sh.exe> from 679the above location. 680 681B<Note.> It may be possible to use some other sh-compatible shell (untested). 682 683=back 684 685After you installed the components you needed and updated the 686F<Config.sys> correspondingly, you need to hand-edit 687F<Config.pm>. This file resides somewhere deep in the location you 688installed your perl library, find it out by 689 690 perl -MConfig -le "print $INC{'Config.pm'}" 691 692You need to correct all the entries which look like file paths (they 693currently start with C<f:/>). 694 695=head2 B<Warning> 696 697The automatic and manual perl installation leave precompiled paths 698inside perl executables. While these paths are overwritable (see 699L</"C<PERLLIB_PREFIX>">, L</"C<PERL_SH_DIR>">), some people may prefer 700binary editing of paths inside the executables/DLLs. 701 702=head1 Accessing documentation 703 704Depending on how you built/installed perl you may have (otherwise 705identical) Perl documentation in the following formats: 706 707=head2 OS/2 F<.INF> file 708 709Most probably the most convenient form. Under OS/2 view it as 710 711 view perl 712 view perl perlfunc 713 view perl less 714 view perl ExtUtils::MakeMaker 715 716(currently the last two may hit a wrong location, but this may improve 717soon). Under Win* see L</"SYNOPSIS">. 718 719If you want to build the docs yourself, and have I<OS/2 toolkit>, run 720 721 pod2ipf > perl.ipf 722 723in F</perllib/lib/pod> directory, then 724 725 ipfc /inf perl.ipf 726 727(Expect a lot of errors during the both steps.) Now move it on your 728BOOKSHELF path. 729 730=head2 Plain text 731 732If you have perl documentation in the source form, perl utilities 733installed, and GNU groff installed, you may use 734 735 perldoc perlfunc 736 perldoc less 737 perldoc ExtUtils::MakeMaker 738 739to access the perl documentation in the text form (note that you may get 740better results using perl manpages). 741 742Alternately, try running pod2text on F<.pod> files. 743 744=head2 Manpages 745 746If you have F<man> installed on your system, and you installed perl 747manpages, use something like this: 748 749 man perlfunc 750 man 3 less 751 man ExtUtils.MakeMaker 752 753to access documentation for different components of Perl. Start with 754 755 man perl 756 757Note that dot (F<.>) is used as a package separator for documentation 758for packages, and as usual, sometimes you need to give the section - C<3> 759above - to avoid shadowing by the I<less(1) manpage>. 760 761Make sure that the directory B<above> the directory with manpages is 762on our C<MANPATH>, like this 763 764 set MANPATH=c:/man;f:/perllib/man 765 766for Perl manpages in C<f:/perllib/man/man1/> etc. 767 768=head2 HTML 769 770If you have some WWW browser available, installed the Perl 771documentation in the source form, and Perl utilities, you can build 772HTML docs. Cd to directory with F<.pod> files, and do like this 773 774 cd f:/perllib/lib/pod 775 pod2html 776 777After this you can direct your browser the file F<perl.html> in this 778directory, and go ahead with reading docs, like this: 779 780 explore file:///f:/perllib/lib/pod/perl.html 781 782Alternatively you may be able to get these docs prebuilt from CPAN. 783 784=head2 GNU C<info> files 785 786Users of Emacs would appreciate it very much, especially with 787C<CPerl> mode loaded. You need to get latest C<pod2texi> from C<CPAN>, 788or, alternately, the prebuilt info pages. 789 790=head2 F<PDF> files 791 792for C<Acrobat> are available on CPAN (may be for slightly older version of 793perl). 794 795=head2 C<LaTeX> docs 796 797can be constructed using C<pod2latex>. 798 799=head1 BUILD 800 801Here we discuss how to build Perl under OS/2. 802 803=head2 The short story 804 805Assume that you are a seasoned porter, so are sure that all the necessary 806tools are already present on your system, and you know how to get the Perl 807source distribution. Untar it, change to the extract directory, and 808 809 gnupatch -p0 < os2\diff.configure 810 sh Configure -des -D prefix=f:/perllib 811 make 812 make test 813 make install 814 make aout_test 815 make aout_install 816 817This puts the executables in f:/perllib/bin. Manually move them to the 818C<PATH>, manually move the built F<perl*.dll> to C<LIBPATH> (here for 819Perl DLL F<*> is a not-very-meaningful hex checksum), and run 820 821 make installcmd INSTALLCMDDIR=d:/ir/on/path 822 823Assuming that the C<man>-files were put on an appropriate location, 824this completes the installation of minimal Perl system. (The binary 825distribution contains also a lot of additional modules, and the 826documentation in INF format.) 827 828What follows is a detailed guide through these steps. 829 830=head2 Prerequisites 831 832You need to have the latest EMX development environment, the full 833GNU tool suite (gawk renamed to awk, and GNU F<find.exe> 834earlier on path than the OS/2 F<find.exe>, same with F<sort.exe>, to 835check use 836 837 find --version 838 sort --version 839 840). You need the latest version of F<pdksh> installed as F<sh.exe>. 841 842Check that you have B<BSD> libraries and headers installed, and - 843optionally - Berkeley DB headers and libraries, and crypt. 844 845Possible locations to get the files: 846 847 848 ftp://ftp.uni-heidelberg.de/pub/os2/unix/ 849 http://hobbes.nmsu.edu/h-browse.php?dir=/pub/os2 850 http://cd.textfiles.com/hobbesos29804/disk1/DEV32/ 851 http://cd.textfiles.com/hobbesos29804/disk1/EMX09C/ 852 853It is reported that the following archives contain enough utils to 854build perl: F<gnufutil.zip>, F<gnusutil.zip>, F<gnututil.zip>, F<gnused.zip>, 855F<gnupatch.zip>, F<gnuawk.zip>, F<gnumake.zip>, F<gnugrep.zip>, F<bsddev.zip> and 856F<ksh527rt.zip> (or a later version). Note that all these utilities are 857known to be available from LEO: 858 859 ftp://crydee.sai.msu.ru/pub/comp/os/os2/leo/gnu/ 860 861Note also that the F<db.lib> and F<db.a> from the EMX distribution 862are not suitable for multi-threaded compile (even single-threaded 863flavor of Perl uses multi-threaded C RTL, for 864compatibility with XFree86-OS/2). Get a corrected one from 865 866 http://www.ilyaz.org/software/os2/db_mt.zip 867 868If you have I<exactly the same version of Perl> installed already, 869make sure that no copies or perl are currently running. Later steps 870of the build may fail since an older version of F<perl.dll> loaded into 871memory may be found. Running C<make test> becomes meaningless, since 872the test are checking a previous build of perl (this situation is detected 873and reported by F<os2/os2_base.t> test). Do not forget to unset 874C<PERL_EMXLOAD_SEC> in environment. 875 876Also make sure that you have F</tmp> directory on the current drive, 877and F<.> directory in your C<LIBPATH>. One may try to correct the 878latter condition by 879 880 set BEGINLIBPATH .\. 881 882if you use something like F<CMD.EXE> or latest versions of 883F<4os2.exe>. (Setting BEGINLIBPATH to just C<.> is ignored by the 884OS/2 kernel.) 885 886Make sure your gcc is good for C<-Zomf> linking: run C<omflibs> 887script in F</emx/lib> directory. 888 889Check that you have link386 installed. It comes standard with OS/2, 890but may be not installed due to customization. If typing 891 892 link386 893 894shows you do not have it, do I<Selective install>, and choose C<Link 895object modules> in I<Optional system utilities/More>. If you get into 896link386 prompts, press C<Ctrl-C> to exit. 897 898=head2 Getting perl source 899 900You need to fetch the latest perl source (including developers 901releases). With some probability it is located in 902 903 http://www.cpan.org/src/ 904 http://www.cpan.org/src/unsupported 905 906If not, you may need to dig in the indices to find it in the directory 907of the current maintainer. 908 909Quick cycle of developers release may break the OS/2 build time to 910time, looking into 911 912 http://www.cpan.org/ports/os2/ 913 914may indicate the latest release which was publicly released by the 915maintainer. Note that the release may include some additional patches 916to apply to the current source of perl. 917 918Extract it like this 919 920 tar vzxf perl5.00409.tar.gz 921 922You may see a message about errors while extracting F<Configure>. This is 923because there is a conflict with a similarly-named file F<configure>. 924 925Change to the directory of extraction. 926 927=head2 Application of the patches 928 929You need to apply the patches in F<./os2/diff.*> like this: 930 931 gnupatch -p0 < os2\diff.configure 932 933You may also need to apply the patches supplied with the binary 934distribution of perl. It also makes sense to look on the 935perl5-porters mailing list for the latest OS/2-related patches (see 936L<http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/>). Such 937patches usually contain strings C</os2/> and C<patch>, so it makes 938sense looking for these strings. 939 940=head2 Hand-editing 941 942You may look into the file F<./hints/os2.sh> and correct anything 943wrong you find there. I do not expect it is needed anywhere. 944 945=head2 Making 946 947 sh Configure -des -D prefix=f:/perllib 948 949C<prefix> means: where to install the resulting perl library. Giving 950correct prefix you may avoid the need to specify C<PERLLIB_PREFIX>, 951see L</"C<PERLLIB_PREFIX>">. 952 953I<Ignore the message about missing C<ln>, and about C<-c> option to 954tr>. The latter is most probably already fixed, if you see it and can trace 955where the latter spurious warning comes from, please inform me. 956 957Now 958 959 make 960 961At some moment the built may die, reporting a I<version mismatch> or 962I<unable to run F<perl>>. This means that you do not have F<.> in 963your LIBPATH, so F<perl.exe> cannot find the needed F<perl67B2.dll> (treat 964these hex digits as line noise). After this is fixed the build 965should finish without a lot of fuss. 966 967=head2 Testing 968 969Now run 970 971 make test 972 973All tests should succeed (with some of them skipped). If you have the 974same version of Perl installed, it is crucial that you have C<.> early 975in your LIBPATH (or in BEGINLIBPATH), otherwise your tests will most 976probably test the wrong version of Perl. 977 978Some tests may generate extra messages similar to 979 980=over 4 981 982=item A lot of C<bad free> 983 984in database tests related to Berkeley DB. I<This should be fixed already.> 985If it persists, you may disable this warnings, see L</"C<PERL_BADFREE>">. 986 987=item Process terminated by SIGTERM/SIGINT 988 989This is a standard message issued by OS/2 applications. *nix 990applications die in silence. It is considered to be a feature. One can 991easily disable this by appropriate sighandlers. 992 993However the test engine bleeds these message to screen in unexpected 994moments. Two messages of this kind I<should> be present during 995testing. 996 997=back 998 999To get finer test reports, call 1000 1001 perl t/harness 1002 1003The report with F<io/pipe.t> failing may look like this: 1004 1005 Failed Test Status Wstat Total Fail Failed List of failed 1006 ------------------------------------------------------------ 1007 io/pipe.t 12 1 8.33% 9 1008 7 tests skipped, plus 56 subtests skipped. 1009 Failed 1/195 test scripts, 99.49% okay. 1/6542 subtests failed, 1010 99.98% okay. 1011 1012The reasons for most important skipped tests are: 1013 1014=over 8 1015 1016=item F<op/fs.t> 1017 1018=over 4 1019 1020=item Z<>18 1021 1022Checks C<atime> and C<mtime> of C<stat()> - unfortunately, HPFS 1023provides only 2sec time granularity (for compatibility with FAT?). 1024 1025=item Z<>25 1026 1027Checks C<truncate()> on a filehandle just opened for write - I do not 1028know why this should or should not work. 1029 1030=back 1031 1032=item F<op/stat.t> 1033 1034Checks C<stat()>. Tests: 1035 1036=over 4 1037 1038=item 4 1039 1040Checks C<atime> and C<mtime> of C<stat()> - unfortunately, HPFS 1041provides only 2sec time granularity (for compatibility with FAT?). 1042 1043=back 1044 1045=back 1046 1047=head2 Installing the built perl 1048 1049If you haven't yet moved C<perl*.dll> onto LIBPATH, do it now. 1050 1051Run 1052 1053 make install 1054 1055It would put the generated files into needed locations. Manually put 1056F<perl.exe>, F<perl__.exe> and F<perl___.exe> to a location on your 1057PATH, F<perl.dll> to a location on your LIBPATH. 1058 1059Run 1060 1061 make installcmd INSTALLCMDDIR=d:/ir/on/path 1062 1063to convert perl utilities to F<.cmd> files and put them on 1064PATH. You need to put F<.EXE>-utilities on path manually. They are 1065installed in C<$prefix/bin>, here C<$prefix> is what you gave to 1066F<Configure>, see L</Making>. 1067 1068If you use C<man>, either move the installed F<*/man/> directories to 1069your C<MANPATH>, or modify C<MANPATH> to match the location. (One 1070could have avoided this by providing a correct C<manpath> option to 1071F<./Configure>, or editing F<./config.sh> between configuring and 1072making steps.) 1073 1074=head2 C<a.out>-style build 1075 1076Proceed as above, but make F<perl_.exe> (see L</"F<perl_.exe>">) by 1077 1078 make perl_ 1079 1080test and install by 1081 1082 make aout_test 1083 make aout_install 1084 1085Manually put F<perl_.exe> to a location on your PATH. 1086 1087B<Note.> The build process for C<perl_> I<does not know> about all the 1088dependencies, so you should make sure that anything is up-to-date, 1089say, by doing 1090 1091 make perl_dll 1092 1093first. 1094 1095=head1 Building a binary distribution 1096 1097[This section provides a short overview only...] 1098 1099Building should proceed differently depending on whether the version of perl 1100you install is already present and used on your system, or is a new version 1101not yet used. The description below assumes that the version is new, so 1102installing its DLLs and F<.pm> files will not disrupt the operation of your 1103system even if some intermediate steps are not yet fully working. 1104 1105The other cases require a little bit more convoluted procedures. Below I 1106suppose that the current version of Perl is C<5.8.2>, so the executables are 1107named accordingly. 1108 1109=over 1110 1111=item 1. 1112 1113Fully build and test the Perl distribution. Make sure that no tests are 1114failing with C<test> and C<aout_test> targets; fix the bugs in Perl and 1115the Perl test suite detected by these tests. Make sure that C<all_test> 1116make target runs as clean as possible. Check that F<os2/perlrexx.cmd> 1117runs fine. 1118 1119=item 2. 1120 1121Fully install Perl, including C<installcmd> target. Copy the generated DLLs 1122to C<LIBPATH>; copy the numbered Perl executables (as in F<perl5.8.2.exe>) 1123to C<PATH>; copy C<perl_.exe> to C<PATH> as C<perl_5.8.2.exe>. Think whether 1124you need backward-compatibility DLLs. In most cases you do not need to install 1125them yet; but sometime this may simplify the following steps. 1126 1127=item 3. 1128 1129Make sure that C<CPAN.pm> can download files from CPAN. If not, you may need 1130to manually install C<Net::FTP>. 1131 1132=item 4. 1133 1134Install the bundle C<Bundle::OS2_default> 1135 1136 perl5.8.2 -MCPAN -e "install Bundle::OS2_default" < nul |& tee 00cpan_i_1 1137 1138This may take a couple of hours on 1GHz processor (when run the first time). 1139And this should not be necessarily a smooth procedure. Some modules may not 1140specify required dependencies, so one may need to repeat this procedure several 1141times until the results stabilize. 1142 1143 perl5.8.2 -MCPAN -e "install Bundle::OS2_default" < nul |& tee 00cpan_i_2 1144 perl5.8.2 -MCPAN -e "install Bundle::OS2_default" < nul |& tee 00cpan_i_3 1145 1146Even after they stabilize, some tests may fail. 1147 1148Fix as many discovered bugs as possible. Document all the bugs which are not 1149fixed, and all the failures with unknown reasons. Inspect the produced logs 1150F<00cpan_i_1> to find suspiciously skipped tests, and other fishy events. 1151 1152Keep in mind that I<installation> of some modules may fail too: for example, 1153the DLLs to update may be already loaded by F<CPAN.pm>. Inspect the C<install> 1154logs (in the example above F<00cpan_i_1> etc) for errors, and install things 1155manually, as in 1156 1157 cd $CPANHOME/.cpan/build/Digest-MD5-2.31 1158 make install 1159 1160Some distributions may fail some tests, but you may want to install them 1161anyway (as above, or via C<force install> command of C<CPAN.pm> shell-mode). 1162 1163Since this procedure may take quite a long time to complete, it makes sense 1164to "freeze" your CPAN configuration by disabling periodic updates of the 1165local copy of CPAN index: set C<index_expire> to some big value (I use 365), 1166then save the settings 1167 1168 CPAN> o conf index_expire 365 1169 CPAN> o conf commit 1170 1171Reset back to the default value C<1> when you are finished. 1172 1173=item 5. 1174 1175When satisfied with the results, rerun the C<installcmd> target. Now you 1176can copy C<perl5.8.2.exe> to C<perl.exe>, and install the other OMF-build 1177executables: C<perl__.exe> etc. They are ready to be used. 1178 1179=item 6. 1180 1181Change to the C<./pod> directory of the build tree, download the Perl logo 1182F<CamelGrayBig.BMP>, and run 1183 1184 ( perl2ipf > perl.ipf ) |& tee 00ipf 1185 ipfc /INF perl.ipf |& tee 00inf 1186 1187This produces the Perl docs online book C<perl.INF>. Install in on 1188C<BOOKSHELF> path. 1189 1190=item 7. 1191 1192Now is the time to build statically linked executable F<perl_.exe> which 1193includes newly-installed via C<Bundle::OS2_default> modules. Doing testing 1194via C<CPAN.pm> is going to be painfully slow, since it statically links 1195a new executable per XS extension. 1196 1197Here is a possible workaround: create a toplevel F<Makefile.PL> in 1198F<$CPANHOME/.cpan/build/> with contents being (compare with L</Making 1199executables with a custom collection of statically loaded extensions>) 1200 1201 use ExtUtils::MakeMaker; 1202 WriteMakefile NAME => 'dummy'; 1203 1204execute this as 1205 1206 perl_5.8.2.exe Makefile.PL <nul |& tee 00aout_c1 1207 make -k all test <nul |& 00aout_t1 1208 1209Again, this procedure should not be absolutely smooth. Some C<Makefile.PL>'s 1210in subdirectories may be buggy, and would not run as "child" scripts. The 1211interdependency of modules can strike you; however, since non-XS modules 1212are already installed, the prerequisites of most modules have a very good 1213chance to be present. 1214 1215If you discover some glitches, move directories of problematic modules to a 1216different location; if these modules are non-XS modules, you may just ignore 1217them - they are already installed; the remaining, XS, modules you need to 1218install manually one by one. 1219 1220After each such removal you need to rerun the C<Makefile.PL>/C<make> process; 1221usually this procedure converges soon. (But be sure to convert all the 1222necessary external C libraries from F<.lib> format to F<.a> format: run one of 1223 1224 emxaout foo.lib 1225 emximp -o foo.a foo.lib 1226 1227whichever is appropriate.) Also, make sure that the DLLs for external 1228libraries are usable with with executables compiled without C<-Zmtd> options. 1229 1230When you are sure that only a few subdirectories 1231lead to failures, you may want to add C<-j4> option to C<make> to speed up 1232skipping subdirectories with already finished build. 1233 1234When you are satisfied with the results of tests, install the build C libraries 1235for extensions: 1236 1237 make install |& tee 00aout_i 1238 1239Now you can rename the file F<./perl.exe> generated during the last phase 1240to F<perl_5.8.2.exe>; place it on C<PATH>; if there is an inter-dependency 1241between some XS modules, you may need to repeat the C<test>/C<install> loop 1242with this new executable and some excluded modules - until the procedure 1243converges. 1244 1245Now you have all the necessary F<.a> libraries for these Perl modules in the 1246places where Perl builder can find it. Use the perl builder: change to an 1247empty directory, create a "dummy" F<Makefile.PL> again, and run 1248 1249 perl_5.8.2.exe Makefile.PL |& tee 00c 1250 make perl |& tee 00p 1251 1252This should create an executable F<./perl.exe> with all the statically loaded 1253extensions built in. Compare the generated F<perlmain.c> files to make sure 1254that during the iterations the number of loaded extensions only increases. 1255Rename F<./perl.exe> to F<perl_5.8.2.exe> on C<PATH>. 1256 1257When it converges, you got a functional variant of F<perl_5.8.2.exe>; copy it 1258to C<perl_.exe>. You are done with generation of the local Perl installation. 1259 1260=item 8. 1261 1262Make sure that the installed modules are actually installed in the location 1263of the new Perl, and are not inherited from entries of @INC given for 1264inheritance from the older versions of Perl: set C<PERLLIB_582_PREFIX> to 1265redirect the new version of Perl to a new location, and copy the installed 1266files to this new location. Redo the tests to make sure that the versions of 1267modules inherited from older versions of Perl are not needed. 1268 1269Actually, the log output of L<pod2ipf(1)> during the step 6 gives a very detailed 1270info about which modules are loaded from which place; so you may use it as 1271an additional verification tool. 1272 1273Check that some temporary files did not make into the perl install tree. 1274Run something like this 1275 1276 pfind . -f "!(/\.(pm|pl|ix|al|h|a|lib|txt|pod|imp|bs|dll|ld|bs|inc|xbm|yml|cgi|uu|e2x|skip|packlist|eg|cfg|html|pub|enc|all|ini|po|pot)$/i or /^\w+$/") | less 1277 1278in the install tree (both top one and F<sitelib> one). 1279 1280Compress all the DLLs with F<lxlite>. The tiny F<.exe> can be compressed with 1281C</c:max> (the bug only appears when there is a fixup in the last 6 bytes of a 1282page (?); since the tiny executables are much smaller than a page, the bug 1283will not hit). Do not compress C<perl_.exe> - it would not work under DOS. 1284 1285=item 9. 1286 1287Now you can generate the binary distribution. This is done by running the 1288test of the CPAN distribution C<OS2::SoftInstaller>. Tune up the file 1289F<test.pl> to suit the layout of current version of Perl first. Do not 1290forget to pack the necessary external DLLs accordingly. Include the 1291description of the bugs and test suite failures you could not fix. Include 1292the small-stack versions of Perl executables from Perl build directory. 1293 1294Include F<perl5.def> so that people can relink the perl DLL preserving 1295the binary compatibility, or can create compatibility DLLs. Include the diff 1296files (C<diff -pu old new>) of fixes you did so that people can rebuild your 1297version. Include F<perl5.map> so that one can use remote debugging. 1298 1299=item 10. 1300 1301Share what you did with the other people. Relax. Enjoy fruits of your work. 1302 1303=item 11. 1304 1305Brace yourself for thanks, bug reports, hate mail and spam coming as result 1306of the previous step. No good deed should remain unpunished! 1307 1308=back 1309 1310=head1 Building custom F<.EXE> files 1311 1312The Perl executables can be easily rebuilt at any moment. Moreover, one can 1313use the I<embedding> interface (see L<perlembed>) to make very customized 1314executables. 1315 1316=head2 Making executables with a custom collection of statically loaded extensions 1317 1318It is a little bit easier to do so while I<decreasing> the list of statically 1319loaded extensions. We discuss this case only here. 1320 1321=over 1322 1323=item 1. 1324 1325Change to an empty directory, and create a placeholder <Makefile.PL>: 1326 1327 use ExtUtils::MakeMaker; 1328 WriteMakefile NAME => 'dummy'; 1329 1330=item 2. 1331 1332Run it with the flavor of Perl (F<perl.exe> or F<perl_.exe>) you want to 1333rebuild. 1334 1335 perl_ Makefile.PL 1336 1337=item 3. 1338 1339Ask it to create new Perl executable: 1340 1341 make perl 1342 1343(you may need to manually add C<PERLTYPE=-DPERL_CORE> to this commandline on 1344some versions of Perl; the symptom is that the command-line globbing does not 1345work from OS/2 shells with the newly-compiled executable; check with 1346 1347 .\perl.exe -wle "print for @ARGV" * 1348 1349). 1350 1351=item 4. 1352 1353The previous step created F<perlmain.c> which contains a list of newXS() calls 1354near the end. Removing unnecessary calls, and rerunning 1355 1356 make perl 1357 1358will produce a customized executable. 1359 1360=back 1361 1362=head2 Making executables with a custom search-paths 1363 1364The default perl executable is flexible enough to support most usages. 1365However, one may want something yet more flexible; for example, one may want 1366to find Perl DLL relatively to the location of the EXE file; or one may want 1367to ignore the environment when setting the Perl-library search patch, etc. 1368 1369If you fill comfortable with I<embedding> interface (see L<perlembed>), such 1370things are easy to do repeating the steps outlined in L/<Making 1371executables with a custom collection of statically loaded extensions>, and 1372doing more comprehensive edits to main() of F<perlmain.c>. The people with 1373little desire to understand Perl can just rename main(), and do necessary 1374modification in a custom main() which calls the renamed function in appropriate 1375time. 1376 1377However, there is a third way: perl DLL exports the main() function and several 1378callbacks to customize the search path. Below is a complete example of a 1379"Perl loader" which 1380 1381=over 1382 1383=item 1. 1384 1385Looks for Perl DLL in the directory C<$exedir/../dll>; 1386 1387=item 2. 1388 1389Prepends the above directory to C<BEGINLIBPATH>; 1390 1391=item 3. 1392 1393Fails if the Perl DLL found via C<BEGINLIBPATH> is different from what was 1394loaded on step 1; e.g., another process could have loaded it from C<LIBPATH> 1395or from a different value of C<BEGINLIBPATH>. In these cases one needs to 1396modify the setting of the system so that this other process either does not 1397run, or loads the DLL from C<BEGINLIBPATH> with C<LIBPATHSTRICT=T> (available 1398with kernels after September 2000). 1399 1400=item 4. 1401 1402Loads Perl library from C<$exedir/../dll/lib/>. 1403 1404=item 5. 1405 1406Uses Bourne shell from C<$exedir/../dll/sh/ksh.exe>. 1407 1408=back 1409 1410For best results compile the C file below with the same options as the Perl 1411DLL. However, a lot of functionality will work even if the executable is not 1412an EMX applications, e.g., if compiled with 1413 1414 gcc -Wall -DDOSISH -DOS2=1 -O2 -s -Zomf -Zsys perl-starter.c \ 1415 -DPERL_DLL_BASENAME=\"perl312F\" -Zstack 8192 -Zlinker /PM:VIO 1416 1417Here is the sample C file: 1418 1419 #define INCL_DOS 1420 #define INCL_NOPM 1421 /* These are needed for compile if os2.h includes os2tk.h, not 1422 * os2emx.h */ 1423 #define INCL_DOSPROCESS 1424 #include <os2.h> 1425 1426 #include "EXTERN.h" 1427 #define PERL_IN_MINIPERLMAIN_C 1428 #include "perl.h" 1429 1430 static char *me; 1431 HMODULE handle; 1432 1433 static void 1434 die_with(char *msg1, char *msg2, char *msg3, char *msg4) 1435 { 1436 ULONG c; 1437 char *s = " error: "; 1438 1439 DosWrite(2, me, strlen(me), &c); 1440 DosWrite(2, s, strlen(s), &c); 1441 DosWrite(2, msg1, strlen(msg1), &c); 1442 DosWrite(2, msg2, strlen(msg2), &c); 1443 DosWrite(2, msg3, strlen(msg3), &c); 1444 DosWrite(2, msg4, strlen(msg4), &c); 1445 DosWrite(2, "\r\n", 2, &c); 1446 exit(255); 1447 } 1448 1449 typedef ULONG (*fill_extLibpath_t)(int type, 1450 char *pre, 1451 char *post, 1452 int replace, 1453 char *msg); 1454 typedef int (*main_t)(int type, char *argv[], char *env[]); 1455 typedef int (*handler_t)(void* data, int which); 1456 1457 #ifndef PERL_DLL_BASENAME 1458 # define PERL_DLL_BASENAME "perl" 1459 #endif 1460 1461 static HMODULE 1462 load_perl_dll(char *basename) 1463 { 1464 char buf[300], fail[260]; 1465 STRLEN l, dirl; 1466 fill_extLibpath_t f; 1467 ULONG rc_fullname; 1468 HMODULE handle, handle1; 1469 1470 if (_execname(buf, sizeof(buf) - 13) != 0) 1471 die_with("Can't find full path: ", strerror(errno), "", ""); 1472 /* XXXX Fill 'me' with new value */ 1473 l = strlen(buf); 1474 while (l && buf[l-1] != '/' && buf[l-1] != '\\') 1475 l--; 1476 dirl = l - 1; 1477 strcpy(buf + l, basename); 1478 l += strlen(basename); 1479 strcpy(buf + l, ".dll"); 1480 if ( (rc_fullname = DosLoadModule(fail, sizeof fail, buf, &handle)) 1481 != 0 1482 && DosLoadModule(fail, sizeof fail, basename, &handle) != 0 ) 1483 die_with("Can't load DLL ", buf, "", ""); 1484 if (rc_fullname) 1485 return handle; /* was loaded with short name; all is fine */ 1486 if (DosQueryProcAddr(handle, 0, "fill_extLibpath", (PFN*)&f)) 1487 die_with(buf, 1488 ": DLL exports no symbol ", 1489 "fill_extLibpath", 1490 ""); 1491 buf[dirl] = 0; 1492 if (f(0 /*BEGINLIBPATH*/, buf /* prepend */, NULL /* append */, 1493 0 /* keep old value */, me)) 1494 die_with(me, ": prepending BEGINLIBPATH", "", ""); 1495 if (DosLoadModule(fail, sizeof fail, basename, &handle1) != 0) 1496 die_with(me, 1497 ": finding perl DLL again via BEGINLIBPATH", 1498 "", 1499 ""); 1500 buf[dirl] = '\\'; 1501 if (handle1 != handle) { 1502 if (DosQueryModuleName(handle1, sizeof(fail), fail)) 1503 strcpy(fail, "???"); 1504 die_with(buf, 1505 ":\n\tperl DLL via BEGINLIBPATH is different: \n\t", 1506 fail, 1507 "\n\tYou may need to manipulate global BEGINLIBPATH" 1508 " and LIBPATHSTRICT" 1509 "\n\tso that the other copy is loaded via" 1510 BEGINLIBPATH."); 1511 } 1512 return handle; 1513 } 1514 1515 int 1516 main(int argc, char **argv, char **env) 1517 { 1518 main_t f; 1519 handler_t h; 1520 1521 me = argv[0]; 1522 /**/ 1523 handle = load_perl_dll(PERL_DLL_BASENAME); 1524 1525 if (DosQueryProcAddr(handle, 1526 0, 1527 "Perl_OS2_handler_install", 1528 (PFN*)&h)) 1529 die_with(PERL_DLL_BASENAME, 1530 ": DLL exports no symbol ", 1531 "Perl_OS2_handler_install", 1532 ""); 1533 if ( !h((void *)"~installprefix", Perlos2_handler_perllib_from) 1534 || !h((void *)"~dll", Perlos2_handler_perllib_to) 1535 || !h((void *)"~dll/sh/ksh.exe", Perlos2_handler_perl_sh) ) 1536 die_with(PERL_DLL_BASENAME, 1537 ": Can't install @INC manglers", 1538 "", 1539 ""); 1540 if (DosQueryProcAddr(handle, 0, "dll_perlmain", (PFN*)&f)) 1541 die_with(PERL_DLL_BASENAME, 1542 ": DLL exports no symbol ", 1543 "dll_perlmain", 1544 ""); 1545 return f(argc, argv, env); 1546 } 1547 1548=head1 Build FAQ 1549 1550=head2 Some C</> became C<\> in pdksh. 1551 1552You have a very old pdksh. See L</Prerequisites>. 1553 1554=head2 C<'errno'> - unresolved external 1555 1556You do not have MT-safe F<db.lib>. See L</Prerequisites>. 1557 1558=head2 Problems with tr or sed 1559 1560reported with very old version of tr and sed. 1561 1562=head2 Some problem (forget which ;-) 1563 1564You have an older version of F<perl.dll> on your LIBPATH, which 1565broke the build of extensions. 1566 1567=head2 Library ... not found 1568 1569You did not run C<omflibs>. See L</Prerequisites>. 1570 1571=head2 Segfault in make 1572 1573You use an old version of GNU make. See L</Prerequisites>. 1574 1575=head2 op/sprintf test failure 1576 1577This can result from a bug in emx sprintf which was fixed in 0.9d fix 03. 1578 1579=head1 Specific (mis)features of OS/2 port 1580 1581=head2 C<setpriority>, C<getpriority> 1582 1583Note that these functions are compatible with *nix, not with the older 1584ports of '94 - 95. The priorities are absolute, go from 32 to -95, 1585lower is quicker. 0 is the default priority. 1586 1587B<WARNING>. Calling C<getpriority> on a non-existing process could lock 1588the system before Warp3 fixpak22. Starting with Warp3, Perl will use 1589a workaround: it aborts getpriority() if the process is not present. 1590This is not possible on older versions C<2.*>, and has a race 1591condition anyway. 1592 1593=head2 C<system()> 1594 1595Multi-argument form of C<system()> allows an additional numeric 1596argument. The meaning of this argument is described in 1597L<OS2::Process>. 1598 1599When finding a program to run, Perl first asks the OS to look for executables 1600on C<PATH> (OS/2 adds extension F<.exe> if no extension is present). 1601If not found, it looks for a script with possible extensions 1602added in this order: no extension, F<.cmd>, F<.btm>, 1603F<.bat>, F<.pl>. If found, Perl checks the start of the file for magic 1604strings C<"#!"> and C<"extproc ">. If found, Perl uses the rest of the 1605first line as the beginning of the command line to run this script. The 1606only mangling done to the first line is extraction of arguments (currently 1607up to 3), and ignoring of the path-part of the "interpreter" name if it can't 1608be found using the full path. 1609 1610E.g., C<system 'foo', 'bar', 'baz'> may lead Perl to finding 1611F<C:/emx/bin/foo.cmd> with the first line being 1612 1613 extproc /bin/bash -x -c 1614 1615If F</bin/bash.exe> is not found, then Perl looks for an executable F<bash.exe> on 1616C<PATH>. If found in F<C:/emx.add/bin/bash.exe>, then the above system() is 1617translated to 1618 1619 system qw(C:/emx.add/bin/bash.exe -x -c C:/emx/bin/foo.cmd bar baz) 1620 1621One additional translation is performed: instead of F</bin/sh> Perl uses 1622the hardwired-or-customized shell (see L</"C<PERL_SH_DIR>">). 1623 1624The above search for "interpreter" is recursive: if F<bash> executable is not 1625found, but F<bash.btm> is found, Perl will investigate its first line etc. 1626The only hardwired limit on the recursion depth is implicit: there is a limit 16274 on the number of additional arguments inserted before the actual arguments 1628given to system(). In particular, if no additional arguments are specified 1629on the "magic" first lines, then the limit on the depth is 4. 1630 1631If Perl finds that the found executable is of PM type when the 1632current session is not, it will start the new process in a separate session of 1633necessary type. Call via C<OS2::Process> to disable this magic. 1634 1635B<WARNING>. Due to the described logic, you need to explicitly 1636specify F<.com> extension if needed. Moreover, if the executable 1637F<perl5.6.1> is requested, Perl will not look for F<perl5.6.1.exe>. 1638[This may change in the future.] 1639 1640=head2 C<extproc> on the first line 1641 1642If the first chars of a Perl script are C<"extproc ">, this line is treated 1643as C<#!>-line, thus all the switches on this line are processed (twice 1644if script was started via cmd.exe). See L<perlrun/DESCRIPTION>. 1645 1646=head2 Additional modules: 1647 1648L<OS2::Process>, L<OS2::DLL>, L<OS2::REXX>, L<OS2::PrfDB>, L<OS2::ExtAttr>. These 1649modules provide access to additional numeric argument for C<system> 1650and to the information about the running process, 1651to DLLs having functions with REXX signature and to the REXX runtime, to 1652OS/2 databases in the F<.INI> format, and to Extended Attributes. 1653 1654Two additional extensions by Andreas Kaiser, C<OS2::UPM>, and 1655C<OS2::FTP>, are included into C<ILYAZ> directory, mirrored on CPAN. 1656Other OS/2-related extensions are available too. 1657 1658=head2 Prebuilt methods: 1659 1660=over 4 1661 1662=item C<File::Copy::syscopy> 1663 1664used by C<File::Copy::copy>, see L<File::Copy>. 1665 1666=item C<DynaLoader::mod2fname> 1667 1668used by C<DynaLoader> for DLL name mangling. 1669 1670=item C<Cwd::current_drive()> 1671 1672Self explanatory. 1673 1674=item C<Cwd::sys_chdir(name)> 1675 1676leaves drive as it is. 1677 1678=item C<Cwd::change_drive(name)> 1679 1680changes the "current" drive. 1681 1682=item C<Cwd::sys_is_absolute(name)> 1683 1684means has drive letter and is_rooted. 1685 1686=item C<Cwd::sys_is_rooted(name)> 1687 1688means has leading C<[/\\]> (maybe after a drive-letter:). 1689 1690=item C<Cwd::sys_is_relative(name)> 1691 1692means changes with current dir. 1693 1694=item C<Cwd::sys_cwd(name)> 1695 1696Interface to cwd from EMX. Used by C<Cwd::cwd>. 1697 1698=item C<Cwd::sys_abspath(name, dir)> 1699 1700Really really odious function to implement. Returns absolute name of 1701file which would have C<name> if CWD were C<dir>. C<Dir> defaults to the 1702current dir. 1703 1704=item C<Cwd::extLibpath([type])> 1705 1706Get current value of extended library search path. If C<type> is 1707present and positive, works with C<END_LIBPATH>, if negative, works 1708with C<LIBPATHSTRICT>, otherwise with C<BEGIN_LIBPATH>. 1709 1710=item C<Cwd::extLibpath_set( path [, type ] )> 1711 1712Set current value of extended library search path. If C<type> is 1713present and positive, works with <END_LIBPATH>, if negative, works 1714with C<LIBPATHSTRICT>, otherwise with C<BEGIN_LIBPATH>. 1715 1716=item C<OS2::Error(do_harderror,do_exception)> 1717 1718Returns C<undef> if it was not called yet, otherwise bit 1 is 1719set if on the previous call do_harderror was enabled, bit 17202 is set if on previous call do_exception was enabled. 1721 1722This function enables/disables error popups associated with 1723hardware errors (Disk not ready etc.) and software exceptions. 1724 1725I know of no way to find out the state of popups I<before> the first call 1726to this function. 1727 1728=item C<OS2::Errors2Drive(drive)> 1729 1730Returns C<undef> if it was not called yet, otherwise return false if errors 1731were not requested to be written to a hard drive, or the drive letter if 1732this was requested. 1733 1734This function may redirect error popups associated with hardware errors 1735(Disk not ready etc.) and software exceptions to the file POPUPLOG.OS2 at 1736the root directory of the specified drive. Overrides OS2::Error() specified 1737by individual programs. Given argument undef will disable redirection. 1738 1739Has global effect, persists after the application exits. 1740 1741I know of no way to find out the state of redirection of popups to the disk 1742I<before> the first call to this function. 1743 1744=item OS2::SysInfo() 1745 1746Returns a hash with system information. The keys of the hash are 1747 1748 MAX_PATH_LENGTH, MAX_TEXT_SESSIONS, MAX_PM_SESSIONS, 1749 MAX_VDM_SESSIONS, BOOT_DRIVE, DYN_PRI_VARIATION, 1750 MAX_WAIT, MIN_SLICE, MAX_SLICE, PAGE_SIZE, 1751 VERSION_MAJOR, VERSION_MINOR, VERSION_REVISION, 1752 MS_COUNT, TIME_LOW, TIME_HIGH, TOTPHYSMEM, TOTRESMEM, 1753 TOTAVAILMEM, MAXPRMEM, MAXSHMEM, TIMER_INTERVAL, 1754 MAX_COMP_LENGTH, FOREGROUND_FS_SESSION, 1755 FOREGROUND_PROCESS 1756 1757=item OS2::BootDrive() 1758 1759Returns a letter without colon. 1760 1761=item C<OS2::MorphPM(serve)>, C<OS2::UnMorphPM(serve)> 1762 1763Transforms the current application into a PM application and back. 1764The argument true means that a real message loop is going to be served. 1765OS2::MorphPM() returns the PM message queue handle as an integer. 1766 1767See L</"Centralized management of resources"> for additional details. 1768 1769=item C<OS2::Serve_Messages(force)> 1770 1771Fake on-demand retrieval of outstanding PM messages. If C<force> is false, 1772will not dispatch messages if a real message loop is known to 1773be present. Returns number of messages retrieved. 1774 1775Dies with "QUITing..." if WM_QUIT message is obtained. 1776 1777=item C<OS2::Process_Messages(force [, cnt])> 1778 1779Retrieval of PM messages until window creation/destruction. 1780If C<force> is false, will not dispatch messages if a real message loop 1781is known to be present. 1782 1783Returns change in number of windows. If C<cnt> is given, 1784it is incremented by the number of messages retrieved. 1785 1786Dies with "QUITing..." if WM_QUIT message is obtained. 1787 1788=item C<OS2::_control87(new,mask)> 1789 1790the same as L<_control87(3)> of EMX. Takes integers as arguments, returns 1791the previous coprocessor control word as an integer. Only bits in C<new> which 1792are present in C<mask> are changed in the control word. 1793 1794=item OS2::get_control87() 1795 1796gets the coprocessor control word as an integer. 1797 1798=item C<OS2::set_control87_em(new=MCW_EM,mask=MCW_EM)> 1799 1800The variant of OS2::_control87() with default values good for 1801handling exception mask: if no C<mask>, uses exception mask part of C<new> 1802only. If no C<new>, disables all the floating point exceptions. 1803 1804See L</"Misfeatures"> for details. 1805 1806=item C<OS2::DLLname([how [, \&xsub]])> 1807 1808Gives the information about the Perl DLL or the DLL containing the C 1809function bound to by C<&xsub>. The meaning of C<how> is: default (2): 1810full name; 0: handle; 1: module name. 1811 1812=back 1813 1814(Note that some of these may be moved to different libraries - 1815eventually). 1816 1817 1818=head2 Prebuilt variables: 1819 1820=over 4 1821 1822=item $OS2::emx_rev 1823 1824numeric value is the same as _emx_rev of EMX, a string value the same 1825as _emx_vprt (similar to C<0.9c>). 1826 1827=item $OS2::emx_env 1828 1829same as _emx_env of EMX, a number similar to 0x8001. 1830 1831=item $OS2::os_ver 1832 1833a number C<OS_MAJOR + 0.001 * OS_MINOR>. 1834 1835=item $OS2::is_aout 1836 1837true if the Perl library was compiled in AOUT format. 1838 1839=item $OS2::can_fork 1840 1841true if the current executable is an AOUT EMX executable, so Perl can 1842fork. Do not use this, use the portable check for 1843$Config::Config{dfork}. 1844 1845=item $OS2::nsyserror 1846 1847This variable (default is 1) controls whether to enforce the contents 1848of $^E to start with C<SYS0003>-like id. If set to 0, then the string 1849value of $^E is what is available from the OS/2 message file. (Some 1850messages in this file have an C<SYS0003>-like id prepended, some not.) 1851 1852=back 1853 1854=head2 Misfeatures 1855 1856=over 4 1857 1858=item * 1859 1860Since L<flock(3)> is present in EMX, but is not functional, it is 1861emulated by perl. To disable the emulations, set environment variable 1862C<USE_PERL_FLOCK=0>. 1863 1864=item * 1865 1866Here is the list of things which may be "broken" on 1867EMX (from EMX docs): 1868 1869=over 4 1870 1871=item * 1872 1873The functions L<recvmsg(3)>, L<sendmsg(3)>, and L<socketpair(3)> are not 1874implemented. 1875 1876=item * 1877 1878L<sock_init(3)> is not required and not implemented. 1879 1880=item * 1881 1882L<flock(3)> is not yet implemented (dummy function). (Perl has a workaround.) 1883 1884=item * 1885 1886L<kill(3)>: Special treatment of PID=0, PID=1 and PID=-1 is not implemented. 1887 1888=item * 1889 1890L<waitpid(3)>: 1891 1892 WUNTRACED 1893 Not implemented. 1894 waitpid() is not implemented for negative values of PID. 1895 1896=back 1897 1898Note that C<kill -9> does not work with the current version of EMX. 1899 1900=item * 1901 1902See L</"Text-mode filehandles">. 1903 1904=item * 1905 1906Unix-domain sockets on OS/2 live in a pseudo-file-system C</sockets/...>. 1907To avoid a failure to create a socket with a name of a different form, 1908C<"/socket/"> is prepended to the socket name (unless it starts with this 1909already). 1910 1911This may lead to problems later in case the socket is accessed via the 1912"usual" file-system calls using the "initial" name. 1913 1914=item * 1915 1916Apparently, IBM used a compiler (for some period of time around '95?) which 1917changes FP mask right and left. This is not I<that> bad for IBM's 1918programs, but the same compiler was used for DLLs which are used with 1919general-purpose applications. When these DLLs are used, the state of 1920floating-point flags in the application is not predictable. 1921 1922What is much worse, some DLLs change the floating point flags when in 1923_DLLInitTerm() (e.g., F<TCP32IP>). This means that even if you do not I<call> 1924any function in the DLL, just the act of loading this DLL will reset your 1925flags. What is worse, the same compiler was used to compile some HOOK DLLs. 1926Given that HOOK dlls are executed in the context of I<all> the applications 1927in the system, this means a complete unpredictability of floating point 1928flags on systems using such HOOK DLLs. E.g., F<GAMESRVR.DLL> of B<DIVE> 1929origin changes the floating point flags on each write to the TTY of a VIO 1930(windowed text-mode) applications. 1931 1932Some other (not completely debugged) situations when FP flags change include 1933some video drivers (?), and some operations related to creation of the windows. 1934People who code B<OpenGL> may have more experience on this. 1935 1936Perl is generally used in the situation when all the floating-point 1937exceptions are ignored, as is the default under EMX. If they are not ignored, 1938some benign Perl programs would get a C<SIGFPE> and would die a horrible death. 1939 1940To circumvent this, Perl uses two hacks. They help against I<one> type of 1941damage only: FP flags changed when loading a DLL. 1942 1943One of the hacks is to disable floating point exceptions on Perl startup (as 1944is the default with EMX). This helps only with compile-time-linked DLLs 1945changing the flags before main() had a chance to be called. 1946 1947The other hack is to restore FP flags after a call to dlopen(). This helps 1948against similar damage done by DLLs _DLLInitTerm() at runtime. Currently 1949no way to switch these hacks off is provided. 1950 1951=back 1952 1953=head2 Modifications 1954 1955Perl modifies some standard C library calls in the following ways: 1956 1957=over 9 1958 1959=item C<popen> 1960 1961C<my_popen> uses F<sh.exe> if shell is required, cf. L</"C<PERL_SH_DIR>">. 1962 1963=item C<tmpnam> 1964 1965is created using C<TMP> or C<TEMP> environment variable, via 1966C<tempnam>. 1967 1968=item C<tmpfile> 1969 1970If the current directory is not writable, file is created using modified 1971C<tmpnam>, so there may be a race condition. 1972 1973=item C<ctermid> 1974 1975a dummy implementation. 1976 1977=item C<stat> 1978 1979C<os2_stat> special-cases F</dev/tty> and F</dev/con>. 1980 1981=item C<mkdir>, C<rmdir> 1982 1983these EMX functions do not work if the path contains a trailing C</>. 1984Perl contains a workaround for this. 1985 1986=item C<flock> 1987 1988Since L<flock(3)> is present in EMX, but is not functional, it is 1989emulated by perl. To disable the emulations, set environment variable 1990C<USE_PERL_FLOCK=0>. 1991 1992=back 1993 1994=head2 Identifying DLLs 1995 1996All the DLLs built with the current versions of Perl have ID strings 1997identifying the name of the extension, its version, and the version 1998of Perl required for this DLL. Run C<bldlevel DLL-name> to find this 1999info. 2000 2001=head2 Centralized management of resources 2002 2003Since to call certain OS/2 API one needs to have a correctly initialized 2004C<Win> subsystem, OS/2-specific extensions may require getting C<HAB>s and 2005C<HMQ>s. If an extension would do it on its own, another extension could 2006fail to initialize. 2007 2008Perl provides a centralized management of these resources: 2009 2010=over 2011 2012=item C<HAB> 2013 2014To get the HAB, the extension should call C<hab = perl_hab_GET()> in C. After 2015this call is performed, C<hab> may be accessed as C<Perl_hab>. There is 2016no need to release the HAB after it is used. 2017 2018If by some reasons F<perl.h> cannot be included, use 2019 2020 extern int Perl_hab_GET(void); 2021 2022instead. 2023 2024=item C<HMQ> 2025 2026There are two cases: 2027 2028=over 2029 2030=item * 2031 2032the extension needs an C<HMQ> only because some API will not work otherwise. 2033Use C<serve = 0> below. 2034 2035=item * 2036 2037the extension needs an C<HMQ> since it wants to engage in a PM event loop. 2038Use C<serve = 1> below. 2039 2040=back 2041 2042To get an C<HMQ>, the extension should call C<hmq = perl_hmq_GET(serve)> in C. 2043After this call is performed, C<hmq> may be accessed as C<Perl_hmq>. 2044 2045To signal to Perl that HMQ is not needed any more, call 2046C<perl_hmq_UNSET(serve)>. Perl process will automatically morph/unmorph itself 2047into/from a PM process if HMQ is needed/not-needed. Perl will automatically 2048enable/disable C<WM_QUIT> message during shutdown if the message queue is 2049served/not-served. 2050 2051B<NOTE>. If during a shutdown there is a message queue which did not disable 2052WM_QUIT, and which did not process the received WM_QUIT message, the 2053shutdown will be automatically cancelled. Do not call C<perl_hmq_GET(1)> 2054unless you are going to process messages on an orderly basis. 2055 2056=item Treating errors reported by OS/2 API 2057 2058There are two principal conventions (it is useful to call them C<Dos*> 2059and C<Win*> - though this part of the function signature is not always 2060determined by the name of the API) of reporting the error conditions 2061of OS/2 API. Most of C<Dos*> APIs report the error code as the result 2062of the call (so 0 means success, and there are many types of errors). 2063Most of C<Win*> API report success/fail via the result being 2064C<TRUE>/C<FALSE>; to find the reason for the failure one should call 2065WinGetLastError() API. 2066 2067Some C<Win*> entry points also overload a "meaningful" return value 2068with the error indicator; having a 0 return value indicates an error. 2069Yet some other C<Win*> entry points overload things even more, and 0 2070return value may mean a successful call returning a valid value 0, as 2071well as an error condition; in the case of a 0 return value one should 2072call WinGetLastError() API to distinguish a successful call from a 2073failing one. 2074 2075By convention, all the calls to OS/2 API should indicate their 2076failures by resetting $^E. All the Perl-accessible functions which 2077call OS/2 API may be broken into two classes: some die()s when an API 2078error is encountered, the other report the error via a false return 2079value (of course, this does not concern Perl-accessible functions 2080which I<expect> a failure of the OS/2 API call, having some workarounds 2081coded). 2082 2083Obviously, in the situation of the last type of the signature of an OS/2 2084API, it is must more convenient for the users if the failure is 2085indicated by die()ing: one does not need to check $^E to know that 2086something went wrong. If, however, this solution is not desirable by 2087some reason, the code in question should reset $^E to 0 before making 2088this OS/2 API call, so that the caller of this Perl-accessible 2089function has a chance to distinguish a success-but-0-return value from 2090a failure. (One may return undef as an alternative way of reporting 2091an error.) 2092 2093The macros to simplify this type of error propagation are 2094 2095=over 2096 2097=item C<CheckOSError(expr)> 2098 2099Returns true on error, sets $^E. Expects expr() be a call of 2100C<Dos*>-style API. 2101 2102=item C<CheckWinError(expr)> 2103 2104Returns true on error, sets $^E. Expects expr() be a call of 2105C<Win*>-style API. 2106 2107=item C<SaveWinError(expr)> 2108 2109Returns C<expr>, sets $^E from WinGetLastError() if C<expr> is false. 2110 2111=item C<SaveCroakWinError(expr,die,name1,name2)> 2112 2113Returns C<expr>, sets $^E from WinGetLastError() if C<expr> is false, 2114and die()s if C<die> and $^E are true. The message to die is the 2115concatenated strings C<name1> and C<name2>, separated by C<": "> from 2116the contents of $^E. 2117 2118=item C<WinError_2_Perl_rc> 2119 2120Sets C<Perl_rc> to the return value of WinGetLastError(). 2121 2122=item C<FillWinError> 2123 2124Sets C<Perl_rc> to the return value of WinGetLastError(), and sets $^E 2125to the corresponding value. 2126 2127=item C<FillOSError(rc)> 2128 2129Sets C<Perl_rc> to C<rc>, and sets $^E to the corresponding value. 2130 2131=back 2132 2133=item Loading DLLs and ordinals in DLLs 2134 2135Some DLLs are only present in some versions of OS/2, or in some 2136configurations of OS/2. Some exported entry points are present only 2137in DLLs shipped with some versions of OS/2. If these DLLs and entry 2138points were linked directly for a Perl executable/DLL or from a Perl 2139extensions, this binary would work only with the specified 2140versions/setups. Even if these entry points were not needed, the 2141I<load> of the executable (or DLL) would fail. 2142 2143For example, many newer useful APIs are not present in OS/2 v2; many 2144PM-related APIs require DLLs not available on floppy-boot setup. 2145 2146To make these calls fail I<only when the calls are executed>, one 2147should call these API via a dynamic linking API. There is a subsystem 2148in Perl to simplify such type of calls. A large number of entry 2149points available for such linking is provided (see C<entries_ordinals> 2150- and also C<PMWIN_entries> - in F<os2ish.h>). These ordinals can be 2151accessed via the APIs: 2152 2153 CallORD(), DeclFuncByORD(), DeclVoidFuncByORD(), 2154 DeclOSFuncByORD(), DeclWinFuncByORD(), AssignFuncPByORD(), 2155 DeclWinFuncByORD_CACHE(), DeclWinFuncByORD_CACHE_survive(), 2156 DeclWinFuncByORD_CACHE_resetError_survive(), 2157 DeclWinFunc_CACHE(), DeclWinFunc_CACHE_resetError(), 2158 DeclWinFunc_CACHE_survive(), DeclWinFunc_CACHE_resetError_survive() 2159 2160See the header files and the C code in the supplied OS/2-related 2161modules for the details on usage of these functions. 2162 2163Some of these functions also combine dynaloading semantic with the 2164error-propagation semantic discussed above. 2165 2166=back 2167 2168=head1 Perl flavors 2169 2170Because of idiosyncrasies of OS/2 one cannot have all the eggs in the 2171same basket (though EMX environment tries hard to overcome this 2172limitations, so the situation may somehow improve). There are 4 2173executables for Perl provided by the distribution: 2174 2175=head2 F<perl.exe> 2176 2177The main workhorse. This is a chimera executable: it is compiled as an 2178C<a.out>-style executable, but is linked with C<omf>-style dynamic 2179library F<perl.dll>, and with dynamic CRT DLL. This executable is a 2180VIO application. 2181 2182It can load perl dynamic extensions, and it can fork(). 2183 2184B<Note.> Keep in mind that fork() is needed to open a pipe to yourself. 2185 2186=head2 F<perl_.exe> 2187 2188This is a statically linked C<a.out>-style executable. It cannot 2189load dynamic Perl extensions. The executable supplied in binary 2190distributions has a lot of extensions prebuilt, thus the above restriction is 2191important only if you use custom-built extensions. This executable is a VIO 2192application. 2193 2194I<This is the only executable with does not require OS/2.> The 2195friends locked into C<M$> world would appreciate the fact that this 2196executable runs under DOS, Win0.3*, Win0.95 and WinNT with an 2197appropriate extender. See L</"Other OSes">. 2198 2199=head2 F<perl__.exe> 2200 2201This is the same executable as F<perl___.exe>, but it is a PM 2202application. 2203 2204B<Note.> Usually (unless explicitly redirected during the startup) 2205STDIN, STDERR, and STDOUT of a PM 2206application are redirected to F<nul>. However, it is possible to I<see> 2207them if you start C<perl__.exe> from a PM program which emulates a 2208console window, like I<Shell mode> of Emacs or EPM. Thus it I<is 2209possible> to use Perl debugger (see L<perldebug>) to debug your PM 2210application (but beware of the message loop lockups - this will not 2211work if you have a message queue to serve, unless you hook the serving 2212into the getc() function of the debugger). 2213 2214Another way to see the output of a PM program is to run it as 2215 2216 pm_prog args 2>&1 | cat - 2217 2218with a shell I<different> from F<cmd.exe>, so that it does not create 2219a link between a VIO session and the session of C<pm_porg>. (Such a link 2220closes the VIO window.) E.g., this works with F<sh.exe> - or with Perl! 2221 2222 open P, 'pm_prog args 2>&1 |' or die; 2223 print while <P>; 2224 2225The flavor F<perl__.exe> is required if you want to start your program without 2226a VIO window present, but not C<detach>ed (run C<help detach> for more info). 2227Very useful for extensions which use PM, like C<Perl/Tk> or C<OpenGL>. 2228 2229Note also that the differences between PM and VIO executables are only 2230in the I<default> behaviour. One can start I<any> executable in 2231I<any> kind of session by using the arguments C</fs>, C</pm> or 2232C</win> switches of the command C<start> (of F<CMD.EXE> or a similar 2233shell). Alternatively, one can use the numeric first argument of the 2234C<system> Perl function (see L<OS2::Process>). 2235 2236=head2 F<perl___.exe> 2237 2238This is an C<omf>-style executable which is dynamically linked to 2239F<perl.dll> and CRT DLL. I know no advantages of this executable 2240over C<perl.exe>, but it cannot fork() at all. Well, one advantage is 2241that the build process is not so convoluted as with C<perl.exe>. 2242 2243It is a VIO application. 2244 2245=head2 Why strange names? 2246 2247Since Perl processes the C<#!>-line (cf. 2248L<perlrun/DESCRIPTION>, L<perlrun/Command Switches>, 2249L<perldiag/"No Perl script found in input">), it should know when a 2250program I<is a Perl>. There is some naming convention which allows 2251Perl to distinguish correct lines from wrong ones. The above names are 2252almost the only names allowed by this convention which do not contain 2253digits (which have absolutely different semantics). 2254 2255=head2 Why dynamic linking? 2256 2257Well, having several executables dynamically linked to the same huge 2258library has its advantages, but this would not substantiate the 2259additional work to make it compile. The reason is the complicated-to-developers 2260but very quick and convenient-to-users "hard" dynamic linking used by OS/2. 2261 2262There are two distinctive features of the dyna-linking model of OS/2: 2263first, all the references to external functions are resolved at the compile time; 2264second, there is no runtime fixup of the DLLs after they are loaded into memory. 2265The first feature is an enormous advantage over other models: it avoids 2266conflicts when several DLLs used by an application export entries with 2267the same name. In such cases "other" models of dyna-linking just choose 2268between these two entry points using some random criterion - with predictable 2269disasters as results. But it is the second feature which requires the build 2270of F<perl.dll>. 2271 2272The address tables of DLLs are patched only once, when they are 2273loaded. The addresses of the entry points into DLLs are guaranteed to be 2274the same for all the programs which use the same DLL. This removes the 2275runtime fixup - once DLL is loaded, its code is read-only. 2276 2277While this allows some (significant?) performance advantages, this makes life 2278much harder for developers, since the above scheme makes it impossible 2279for a DLL to be "linked" to a symbol in the F<.EXE> file. Indeed, this 2280would need a DLL to have different relocations tables for the 2281(different) executables which use this DLL. 2282 2283However, a dynamically loaded Perl extension is forced to use some symbols 2284from the perl 2285executable, e.g., to know how to find the arguments to the functions: 2286the arguments live on the perl 2287internal evaluation stack. The solution is to put the main code of 2288the interpreter into a DLL, and make the F<.EXE> file which just loads 2289this DLL into memory and supplies command-arguments. The extension DLL 2290cannot link to symbols in F<.EXE>, but it has no problem linking 2291to symbols in the F<.DLL>. 2292 2293This I<greatly> increases the load time for the application (as well as 2294complexity of the compilation). Since interpreter is in a DLL, 2295the C RTL is basically forced to reside in a DLL as well (otherwise 2296extensions would not be able to use CRT). There are some advantages if 2297you use different flavors of perl, such as running F<perl.exe> and 2298F<perl__.exe> simultaneously: they share the memory of F<perl.dll>. 2299 2300B<NOTE>. There is one additional effect which makes DLLs more wasteful: 2301DLLs are loaded in the shared memory region, which is a scarse resource 2302given the 512M barrier of the "standard" OS/2 virtual memory. The code of 2303F<.EXE> files is also shared by all the processes which use the particular 2304F<.EXE>, but they are "shared in the private address space of the process"; 2305this is possible because the address at which different sections 2306of the F<.EXE> file are loaded is decided at compile-time, thus all the 2307processes have these sections loaded at same addresses, and no fixup 2308of internal links inside the F<.EXE> is needed. 2309 2310Since DLLs may be loaded at run time, to have the same mechanism for DLLs 2311one needs to have the address range of I<any of the loaded> DLLs in the 2312system to be available I<in all the processes> which did not load a particular 2313DLL yet. This is why the DLLs are mapped to the shared memory region. 2314 2315=head2 Why chimera build? 2316 2317Current EMX environment does not allow DLLs compiled using Unixish 2318C<a.out> format to export symbols for data (or at least some types of 2319data). This forces C<omf>-style compile of F<perl.dll>. 2320 2321Current EMX environment does not allow F<.EXE> files compiled in 2322C<omf> format to fork(). fork() is needed for exactly three Perl 2323operations: 2324 2325=over 4 2326 2327=item * 2328 2329explicit fork() in the script, 2330 2331=item * 2332 2333C<open FH, "|-"> 2334 2335=item * 2336 2337C<open FH, "-|">, in other words, opening pipes to itself. 2338 2339=back 2340 2341While these operations are not questions of life and death, they are 2342needed for a lot of 2343useful scripts. This forces C<a.out>-style compile of 2344F<perl.exe>. 2345 2346 2347=head1 ENVIRONMENT 2348 2349Here we list environment variables with are either OS/2- and DOS- and 2350Win*-specific, or are more important under OS/2 than under other OSes. 2351 2352=head2 C<PERLLIB_PREFIX> 2353 2354Specific for EMX port. Should have the form 2355 2356 path1;path2 2357 2358or 2359 2360 path1 path2 2361 2362If the beginning of some prebuilt path matches F<path1>, it is 2363substituted with F<path2>. 2364 2365Should be used if the perl library is moved from the default 2366location in preference to C<PERL(5)LIB>, since this would not leave wrong 2367entries in @INC. For example, if the compiled version of perl looks for @INC 2368in F<f:/perllib/lib>, and you want to install the library in 2369F<h:/opt/gnu>, do 2370 2371 set PERLLIB_PREFIX=f:/perllib/lib;h:/opt/gnu 2372 2373This will cause Perl with the prebuilt @INC of 2374 2375 f:/perllib/lib/5.00553/os2 2376 f:/perllib/lib/5.00553 2377 f:/perllib/lib/site_perl/5.00553/os2 2378 f:/perllib/lib/site_perl/5.00553 2379 . 2380 2381to use the following @INC: 2382 2383 h:/opt/gnu/5.00553/os2 2384 h:/opt/gnu/5.00553 2385 h:/opt/gnu/site_perl/5.00553/os2 2386 h:/opt/gnu/site_perl/5.00553 2387 . 2388 2389=head2 C<PERL_BADLANG> 2390 2391If 0, perl ignores setlocale() failing. May be useful with some 2392strange I<locale>s. 2393 2394=head2 C<PERL_BADFREE> 2395 2396If 0, perl would not warn of in case of unwarranted free(). With older 2397perls this might be 2398useful in conjunction with the module DB_File, which was buggy when 2399dynamically linked and OMF-built. 2400 2401Should not be set with newer Perls, since this may hide some I<real> problems. 2402 2403=head2 C<PERL_SH_DIR> 2404 2405Specific for EMX port. Gives the directory part of the location for 2406F<sh.exe>. 2407 2408=head2 C<USE_PERL_FLOCK> 2409 2410Specific for EMX port. Since L<flock(3)> is present in EMX, but is not 2411functional, it is emulated by perl. To disable the emulations, set 2412environment variable C<USE_PERL_FLOCK=0>. 2413 2414=head2 C<TMP> or C<TEMP> 2415 2416Specific for EMX port. Used as storage place for temporary files. 2417 2418=head1 Evolution 2419 2420Here we list major changes which could make you by surprise. 2421 2422=head2 Text-mode filehandles 2423 2424Starting from version 5.8, Perl uses a builtin translation layer for 2425text-mode files. This replaces the efficient well-tested EMX layer by 2426some code which should be best characterized as a "quick hack". 2427 2428In addition to possible bugs and an inability to follow changes to the 2429translation policy with off/on switches of TERMIO translation, this 2430introduces a serious incompatible change: before sysread() on 2431text-mode filehandles would go through the translation layer, now it 2432would not. 2433 2434=head2 Priorities 2435 2436C<setpriority> and C<getpriority> are not compatible with earlier 2437ports by Andreas Kaiser. See C<"setpriority, getpriority">. 2438 2439=head2 DLL name mangling: pre 5.6.2 2440 2441With the release 5.003_01 the dynamically loadable libraries 2442should be rebuilt when a different version of Perl is compiled. In particular, 2443DLLs (including F<perl.dll>) are now created with the names 2444which contain a checksum, thus allowing workaround for OS/2 scheme of 2445caching DLLs. 2446 2447It may be possible to code a simple workaround which would 2448 2449=over 2450 2451=item * 2452 2453find the old DLLs looking through the old @INC; 2454 2455=item * 2456 2457mangle the names according to the scheme of new perl and copy the DLLs to 2458these names; 2459 2460=item * 2461 2462edit the internal C<LX> tables of DLL to reflect the change of the name 2463(probably not needed for Perl extension DLLs, since the internally coded names 2464are not used for "specific" DLLs, they used only for "global" DLLs). 2465 2466=item * 2467 2468edit the internal C<IMPORT> tables and change the name of the "old" 2469F<perl????.dll> to the "new" F<perl????.dll>. 2470 2471=back 2472 2473=head2 DLL name mangling: 5.6.2 and beyond 2474 2475In fact mangling of I<extension> DLLs was done due to misunderstanding 2476of the OS/2 dynaloading model. OS/2 (effectively) maintains two 2477different tables of loaded DLL: 2478 2479=over 2480 2481=item Global DLLs 2482 2483those loaded by the base name from C<LIBPATH>; including those 2484associated at link time; 2485 2486=item specific DLLs 2487 2488loaded by the full name. 2489 2490=back 2491 2492When resolving a request for a global DLL, the table of already-loaded 2493specific DLLs is (effectively) ignored; moreover, specific DLLs are 2494I<always> loaded from the prescribed path. 2495 2496There is/was a minor twist which makes this scheme fragile: what to do 2497with DLLs loaded from 2498 2499=over 2500 2501=item C<BEGINLIBPATH> and C<ENDLIBPATH> 2502 2503(which depend on the process) 2504 2505=item F<.> from C<LIBPATH> 2506 2507which I<effectively> depends on the process (although C<LIBPATH> is the 2508same for all the processes). 2509 2510=back 2511 2512Unless C<LIBPATHSTRICT> is set to C<T> (and the kernel is after 25132000/09/01), such DLLs are considered to be global. When loading a 2514global DLL it is first looked in the table of already-loaded global 2515DLLs. Because of this the fact that one executable loaded a DLL from 2516C<BEGINLIBPATH> and C<ENDLIBPATH>, or F<.> from C<LIBPATH> may affect 2517I<which> DLL is loaded when I<another> executable requests a DLL with 2518the same name. I<This> is the reason for version-specific mangling of 2519the DLL name for perl DLL. 2520 2521Since the Perl extension DLLs are always loaded with the full path, 2522there is no need to mangle their names in a version-specific ways: 2523their directory already reflects the corresponding version of perl, 2524and @INC takes into account binary compatibility with older version. 2525Starting from C<5.6.2> the name mangling scheme is fixed to be the 2526same as for Perl 5.005_53 (same as in a popular binary release). Thus 2527new Perls will be able to I<resolve the names> of old extension DLLs 2528if @INC allows finding their directories. 2529 2530However, this still does not guarantee that these DLL may be loaded. 2531The reason is the mangling of the name of the I<Perl DLL>. And since 2532the extension DLLs link with the Perl DLL, extension DLLs for older 2533versions would load an older Perl DLL, and would most probably 2534segfault (since the data in this DLL is not properly initialized). 2535 2536There is a partial workaround (which can be made complete with newer 2537OS/2 kernels): create a forwarder DLL with the same name as the DLL of 2538the older version of Perl, which forwards the entry points to the 2539newer Perl's DLL. Make this DLL accessible on (say) the C<BEGINLIBPATH> of 2540the new Perl executable. When the new executable accesses old Perl's 2541extension DLLs, they would request the old Perl's DLL by name, get the 2542forwarder instead, so effectively will link with the currently running 2543(new) Perl DLL. 2544 2545This may break in two ways: 2546 2547=over 2548 2549=item * 2550 2551Old perl executable is started when a new executable is running has 2552loaded an extension compiled for the old executable (ouph!). In this 2553case the old executable will get a forwarder DLL instead of the old 2554perl DLL, so would link with the new perl DLL. While not directly 2555fatal, it will behave the same as new executable. This beats the whole 2556purpose of explicitly starting an old executable. 2557 2558=item * 2559 2560A new executable loads an extension compiled for the old executable 2561when an old perl executable is running. In this case the extension 2562will not pick up the forwarder - with fatal results. 2563 2564=back 2565 2566With support for C<LIBPATHSTRICT> this may be circumvented - unless 2567one of DLLs is started from F<.> from C<LIBPATH> (I do not know 2568whether C<LIBPATHSTRICT> affects this case). 2569 2570B<REMARK>. Unless newer kernels allow F<.> in C<BEGINLIBPATH> (older 2571do not), this mess cannot be completely cleaned. (It turns out that 2572as of the beginning of 2002, F<.> is not allowed, but F<.\.> is - and 2573it has the same effect.) 2574 2575 2576B<REMARK>. C<LIBPATHSTRICT>, C<BEGINLIBPATH> and C<ENDLIBPATH> are 2577not environment variables, although F<cmd.exe> emulates them on C<SET 2578...> lines. From Perl they may be accessed by 2579L<Cwd::extLibpath|/Cwd::extLibpath([type])> and 2580L<Cwd::extLibpath_set|/Cwd::extLibpath_set( path [, type ] )>. 2581 2582=head2 DLL forwarder generation 2583 2584Assume that the old DLL is named F<perlE0AC.dll> (as is one for 25855.005_53), and the new version is 5.6.1. Create a file 2586F<perl5shim.def-leader> with 2587 2588 LIBRARY 'perlE0AC' INITINSTANCE TERMINSTANCE 2589 DESCRIPTION '@#perl5-porters@perl.org:5.006001#@ Perl module for 5.00553 -> Perl 5.6.1 forwarder' 2590 CODE LOADONCALL 2591 DATA LOADONCALL NONSHARED MULTIPLE 2592 EXPORTS 2593 2594modifying the versions/names as needed. Run 2595 2596 perl -wnle "next if 0../EXPORTS/; print qq( \"$1\") 2597 if /\"(\w+)\"/" perl5.def >lst 2598 2599in the Perl build directory (to make the DLL smaller replace perl5.def 2600with the definition file for the older version of Perl if present). 2601 2602 cat perl5shim.def-leader lst >perl5shim.def 2603 gcc -Zomf -Zdll -o perlE0AC.dll perl5shim.def -s -llibperl 2604 2605(ignore multiple C<warning L4085>). 2606 2607=head2 Threading 2608 2609As of release 5.003_01 perl is linked to multithreaded C RTL 2610DLL. If perl itself is not compiled multithread-enabled, so will not be perl's 2611malloc(). However, extensions may use multiple thread on their own 2612risk. 2613 2614This was needed to compile C<Perl/Tk> for XFree86-OS/2 out-of-the-box, and 2615link with DLLs for other useful libraries, which typically are compiled 2616with C<-Zmt -Zcrtdll>. 2617 2618=head2 Calls to external programs 2619 2620Due to a popular demand the perl external program calling has been 2621changed wrt Andreas Kaiser's port. I<If> perl needs to call an 2622external program I<via shell>, the F<f:/bin/sh.exe> will be called, or 2623whatever is the override, see L</"C<PERL_SH_DIR>">. 2624 2625Thus means that you need to get some copy of a F<sh.exe> as well (I 2626use one from pdksh). The path F<F:/bin> above is set up automatically during 2627the build to a correct value on the builder machine, but is 2628overridable at runtime, 2629 2630B<Reasons:> a consensus on C<perl5-porters> was that perl should use 2631one non-overridable shell per platform. The obvious choices for OS/2 2632are F<cmd.exe> and F<sh.exe>. Having perl build itself would be impossible 2633with F<cmd.exe> as a shell, thus I picked up C<sh.exe>. This assures almost 2634100% compatibility with the scripts coming from *nix. As an added benefit 2635this works as well under DOS if you use DOS-enabled port of pdksh 2636(see L</Prerequisites>). 2637 2638B<Disadvantages:> currently F<sh.exe> of pdksh calls external programs 2639via fork()/exec(), and there is I<no> functioning exec() on 2640OS/2. exec() is emulated by EMX by an asynchronous call while the caller 2641waits for child completion (to pretend that the C<pid> did not change). This 2642means that 1 I<extra> copy of F<sh.exe> is made active via fork()/exec(), 2643which may lead to some resources taken from the system (even if we do 2644not count extra work needed for fork()ing). 2645 2646Note that this a lesser issue now when we do not spawn F<sh.exe> 2647unless needed (metachars found). 2648 2649One can always start F<cmd.exe> explicitly via 2650 2651 system 'cmd', '/c', 'mycmd', 'arg1', 'arg2', ... 2652 2653If you need to use F<cmd.exe>, and do not want to hand-edit thousands of your 2654scripts, the long-term solution proposed on p5-p is to have a directive 2655 2656 use OS2::Cmd; 2657 2658which will override system(), exec(), C<``>, and 2659C<open(,'...|')>. With current perl you may override only system(), 2660readpipe() - the explicit version of C<``>, and maybe exec(). The code 2661will substitute the one-argument call to system() by 2662C<CORE::system('cmd.exe', '/c', shift)>. 2663 2664If you have some working code for C<OS2::Cmd>, please send it to me, 2665I will include it into distribution. I have no need for such a module, so 2666cannot test it. 2667 2668For the details of the current situation with calling external programs, 2669see L<Starting OSE<sol>2 (and DOS) programs under Perl>. Set us mention a couple 2670of features: 2671 2672=over 4 2673 2674=item * 2675 2676External scripts may be called by their basename. Perl will try the same 2677extensions as when processing B<-S> command-line switch. 2678 2679=item * 2680 2681External scripts starting with C<#!> or C<extproc > will be executed directly, 2682without calling the shell, by calling the program specified on the rest of 2683the first line. 2684 2685=back 2686 2687=head2 Memory allocation 2688 2689Perl uses its own malloc() under OS/2 - interpreters are usually malloc-bound 2690for speed, but perl is not, since its malloc is lightning-fast. 2691Perl-memory-usage-tuned benchmarks show that Perl's malloc is 5 times quicker 2692than EMX one. I do not have convincing data about memory footprint, but 2693a (pretty random) benchmark showed that Perl's one is 5% better. 2694 2695Combination of perl's malloc() and rigid DLL name resolution creates 2696a special problem with library functions which expect their return value to 2697be free()d by system's free(). To facilitate extensions which need to call 2698such functions, system memory-allocation functions are still available with 2699the prefix C<emx_> added. (Currently only DLL perl has this, it should 2700propagate to F<perl_.exe> shortly.) 2701 2702=head2 Threads 2703 2704One can build perl with thread support enabled by providing C<-D usethreads> 2705option to F<Configure>. Currently OS/2 support of threads is very 2706preliminary. 2707 2708Most notable problems: 2709 2710=over 4 2711 2712=item C<COND_WAIT> 2713 2714may have a race condition (but probably does not due to edge-triggered 2715nature of OS/2 Event semaphores). (Needs a reimplementation (in terms of chaining 2716waiting threads, with the linked list stored in per-thread structure?)?) 2717 2718=item F<os2.c> 2719 2720has a couple of static variables used in OS/2-specific functions. (Need to be 2721moved to per-thread structure, or serialized?) 2722 2723=back 2724 2725Note that these problems should not discourage experimenting, since they 2726have a low probability of affecting small programs. 2727 2728=head1 BUGS 2729 2730This description is not updated often (since 5.6.1?), see F<./os2/Changes> 2731for more info. 2732 2733=cut 2734 2735OS/2 extensions 2736~~~~~~~~~~~~~~~ 2737I include 3 extensions by Andreas Kaiser, OS2::REXX, OS2::UPM, and OS2::FTP, 2738into my ftp directory, mirrored on CPAN. I made 2739some minor changes needed to compile them by standard tools. I cannot 2740test UPM and FTP, so I will appreciate your feedback. Other extensions 2741there are OS2::ExtAttr, OS2::PrfDB for tied access to EAs and .INI 2742files - and maybe some other extensions at the time you read it. 2743 2744Note that OS2 perl defines 2 pseudo-extension functions 2745OS2::Copy::copy and DynaLoader::mod2fname (many more now, see 2746L</Prebuilt methods>). 2747 2748The -R switch of older perl is deprecated. If you need to call a REXX code 2749which needs access to variables, include the call into a REXX compartment 2750created by 2751 REXX_call {...block...}; 2752 2753Two new functions are supported by REXX code, 2754 REXX_eval 'string'; 2755 REXX_eval_with 'string', REXX_function_name => \&perl_sub_reference; 2756 2757If you have some other extensions you want to share, send the code to 2758me. At least two are available: tied access to EA's, and tied access 2759to system databases. 2760 2761=head1 AUTHOR 2762 2763Ilya Zakharevich, cpan@ilyaz.org 2764 2765=head1 SEE ALSO 2766 2767perl(1). 2768 2769=cut 2770 2771