targets.texi revision 1.1.1.2
1@section Targets 2 3 4@strong{Description}@* 5Each port of BFD to a different machine requires the creation 6of a target back end. All the back end provides to the root 7part of BFD is a structure containing pointers to functions 8which perform certain low level operations on files. BFD 9translates the applications's requests through a pointer into 10calls to the back end routines. 11 12When a file is opened with @code{bfd_openr}, its format and 13target are unknown. BFD uses various mechanisms to determine 14how to interpret the file. The operations performed are: 15 16@itemize @bullet 17 18@item 19Create a BFD by calling the internal routine 20@code{_bfd_new_bfd}, then call @code{bfd_find_target} with the 21target string supplied to @code{bfd_openr} and the new BFD pointer. 22 23@item 24If a null target string was provided to @code{bfd_find_target}, 25look up the environment variable @code{GNUTARGET} and use 26that as the target string. 27 28@item 29If the target string is still @code{NULL}, or the target string is 30@code{default}, then use the first item in the target vector 31as the target type, and set @code{target_defaulted} in the BFD to 32cause @code{bfd_check_format} to loop through all the targets. 33@xref{bfd_target}. @xref{Formats}. 34 35@item 36Otherwise, inspect the elements in the target vector 37one by one, until a match on target name is found. When found, 38use it. 39 40@item 41Otherwise return the error @code{bfd_error_invalid_target} to 42@code{bfd_openr}. 43 44@item 45@code{bfd_openr} attempts to open the file using 46@code{bfd_open_file}, and returns the BFD. 47@end itemize 48Once the BFD has been opened and the target selected, the file 49format may be determined. This is done by calling 50@code{bfd_check_format} on the BFD with a suggested format. 51If @code{target_defaulted} has been set, each possible target 52type is tried to see if it recognizes the specified format. 53@code{bfd_check_format} returns @code{TRUE} when the caller guesses right. 54@menu 55* bfd_target:: 56@end menu 57 58@node bfd_target, , Targets, Targets 59 60@subsection bfd_target 61 62 63@strong{Description}@* 64This structure contains everything that BFD knows about a 65target. It includes things like its byte order, name, and which 66routines to call to do various operations. 67 68Every BFD points to a target structure with its @code{xvec} 69member. 70 71The macros below are used to dispatch to functions through the 72@code{bfd_target} vector. They are used in a number of macros further 73down in @file{bfd.h}, and are also used when calling various 74routines by hand inside the BFD implementation. The @var{arglist} 75argument must be parenthesized; it contains all the arguments 76to the called function. 77 78They make the documentation (more) unpleasant to read, so if 79someone wants to fix this and not break the above, please do. 80@example 81#define BFD_SEND(bfd, message, arglist) \ 82 ((*((bfd)->xvec->message)) arglist) 83 84#ifdef DEBUG_BFD_SEND 85#undef BFD_SEND 86#define BFD_SEND(bfd, message, arglist) \ 87 (((bfd) && (bfd)->xvec && (bfd)->xvec->message) ? \ 88 ((*((bfd)->xvec->message)) arglist) : \ 89 (bfd_assert (__FILE__,__LINE__), NULL)) 90#endif 91@end example 92For operations which index on the BFD format: 93@example 94#define BFD_SEND_FMT(bfd, message, arglist) \ 95 (((bfd)->xvec->message[(int) ((bfd)->format)]) arglist) 96 97#ifdef DEBUG_BFD_SEND 98#undef BFD_SEND_FMT 99#define BFD_SEND_FMT(bfd, message, arglist) \ 100 (((bfd) && (bfd)->xvec && (bfd)->xvec->message) ? \ 101 (((bfd)->xvec->message[(int) ((bfd)->format)]) arglist) : \ 102 (bfd_assert (__FILE__,__LINE__), NULL)) 103#endif 104 105@end example 106This is the structure which defines the type of BFD this is. The 107@code{xvec} member of the struct @code{bfd} itself points here. Each 108module that implements access to a different target under BFD, 109defines one of these. 110 111FIXME, these names should be rationalised with the names of 112the entry points which call them. Too bad we can't have one 113macro to define them both! 114@example 115enum bfd_flavour 116@{ 117 bfd_target_unknown_flavour, 118 bfd_target_aout_flavour, 119 bfd_target_coff_flavour, 120 bfd_target_ecoff_flavour, 121 bfd_target_xcoff_flavour, 122 bfd_target_elf_flavour, 123 bfd_target_ieee_flavour, 124 bfd_target_nlm_flavour, 125 bfd_target_oasys_flavour, 126 bfd_target_tekhex_flavour, 127 bfd_target_srec_flavour, 128 bfd_target_verilog_flavour, 129 bfd_target_ihex_flavour, 130 bfd_target_som_flavour, 131 bfd_target_os9k_flavour, 132 bfd_target_versados_flavour, 133 bfd_target_msdos_flavour, 134 bfd_target_ovax_flavour, 135 bfd_target_evax_flavour, 136 bfd_target_mmo_flavour, 137 bfd_target_mach_o_flavour, 138 bfd_target_pef_flavour, 139 bfd_target_pef_xlib_flavour, 140 bfd_target_sym_flavour 141@}; 142 143enum bfd_endian @{ BFD_ENDIAN_BIG, BFD_ENDIAN_LITTLE, BFD_ENDIAN_UNKNOWN @}; 144 145/* Forward declaration. */ 146typedef struct bfd_link_info _bfd_link_info; 147 148typedef struct bfd_target 149@{ 150 /* Identifies the kind of target, e.g., SunOS4, Ultrix, etc. */ 151 char *name; 152 153 /* The "flavour" of a back end is a general indication about 154 the contents of a file. */ 155 enum bfd_flavour flavour; 156 157 /* The order of bytes within the data area of a file. */ 158 enum bfd_endian byteorder; 159 160 /* The order of bytes within the header parts of a file. */ 161 enum bfd_endian header_byteorder; 162 163 /* A mask of all the flags which an executable may have set - 164 from the set @code{BFD_NO_FLAGS}, @code{HAS_RELOC}, ...@code{D_PAGED}. */ 165 flagword object_flags; 166 167 /* A mask of all the flags which a section may have set - from 168 the set @code{SEC_NO_FLAGS}, @code{SEC_ALLOC}, ...@code{SET_NEVER_LOAD}. */ 169 flagword section_flags; 170 171 /* The character normally found at the front of a symbol. 172 (if any), perhaps `_'. */ 173 char symbol_leading_char; 174 175 /* The pad character for file names within an archive header. */ 176 char ar_pad_char; 177 178 /* The maximum number of characters in an archive header. */ 179 unsigned short ar_max_namelen; 180 181 /* Entries for byte swapping for data. These are different from the 182 other entry points, since they don't take a BFD as the first argument. 183 Certain other handlers could do the same. */ 184 bfd_uint64_t (*bfd_getx64) (const void *); 185 bfd_int64_t (*bfd_getx_signed_64) (const void *); 186 void (*bfd_putx64) (bfd_uint64_t, void *); 187 bfd_vma (*bfd_getx32) (const void *); 188 bfd_signed_vma (*bfd_getx_signed_32) (const void *); 189 void (*bfd_putx32) (bfd_vma, void *); 190 bfd_vma (*bfd_getx16) (const void *); 191 bfd_signed_vma (*bfd_getx_signed_16) (const void *); 192 void (*bfd_putx16) (bfd_vma, void *); 193 194 /* Byte swapping for the headers. */ 195 bfd_uint64_t (*bfd_h_getx64) (const void *); 196 bfd_int64_t (*bfd_h_getx_signed_64) (const void *); 197 void (*bfd_h_putx64) (bfd_uint64_t, void *); 198 bfd_vma (*bfd_h_getx32) (const void *); 199 bfd_signed_vma (*bfd_h_getx_signed_32) (const void *); 200 void (*bfd_h_putx32) (bfd_vma, void *); 201 bfd_vma (*bfd_h_getx16) (const void *); 202 bfd_signed_vma (*bfd_h_getx_signed_16) (const void *); 203 void (*bfd_h_putx16) (bfd_vma, void *); 204 205 /* Format dependent routines: these are vectors of entry points 206 within the target vector structure, one for each format to check. */ 207 208 /* Check the format of a file being read. Return a @code{bfd_target *} or zero. */ 209 const struct bfd_target *(*_bfd_check_format[bfd_type_end]) (bfd *); 210 211 /* Set the format of a file being written. */ 212 bfd_boolean (*_bfd_set_format[bfd_type_end]) (bfd *); 213 214 /* Write cached information into a file being written, at @code{bfd_close}. */ 215 bfd_boolean (*_bfd_write_contents[bfd_type_end]) (bfd *); 216 217@end example 218The general target vector. These vectors are initialized using the 219BFD_JUMP_TABLE macros. 220@example 221 222 /* Generic entry points. */ 223#define BFD_JUMP_TABLE_GENERIC(NAME) \ 224 NAME##_close_and_cleanup, \ 225 NAME##_bfd_free_cached_info, \ 226 NAME##_new_section_hook, \ 227 NAME##_get_section_contents, \ 228 NAME##_get_section_contents_in_window 229 230 /* Called when the BFD is being closed to do any necessary cleanup. */ 231 bfd_boolean (*_close_and_cleanup) (bfd *); 232 /* Ask the BFD to free all cached information. */ 233 bfd_boolean (*_bfd_free_cached_info) (bfd *); 234 /* Called when a new section is created. */ 235 bfd_boolean (*_new_section_hook) (bfd *, sec_ptr); 236 /* Read the contents of a section. */ 237 bfd_boolean (*_bfd_get_section_contents) 238 (bfd *, sec_ptr, void *, file_ptr, bfd_size_type); 239 bfd_boolean (*_bfd_get_section_contents_in_window) 240 (bfd *, sec_ptr, bfd_window *, file_ptr, bfd_size_type); 241 242 /* Entry points to copy private data. */ 243#define BFD_JUMP_TABLE_COPY(NAME) \ 244 NAME##_bfd_copy_private_bfd_data, \ 245 NAME##_bfd_merge_private_bfd_data, \ 246 _bfd_generic_init_private_section_data, \ 247 NAME##_bfd_copy_private_section_data, \ 248 NAME##_bfd_copy_private_symbol_data, \ 249 NAME##_bfd_copy_private_header_data, \ 250 NAME##_bfd_set_private_flags, \ 251 NAME##_bfd_print_private_bfd_data 252 253 /* Called to copy BFD general private data from one object file 254 to another. */ 255 bfd_boolean (*_bfd_copy_private_bfd_data) (bfd *, bfd *); 256 /* Called to merge BFD general private data from one object file 257 to a common output file when linking. */ 258 bfd_boolean (*_bfd_merge_private_bfd_data) (bfd *, bfd *); 259 /* Called to initialize BFD private section data from one object file 260 to another. */ 261#define bfd_init_private_section_data(ibfd, isec, obfd, osec, link_info) \ 262 BFD_SEND (obfd, _bfd_init_private_section_data, (ibfd, isec, obfd, osec, link_info)) 263 bfd_boolean (*_bfd_init_private_section_data) 264 (bfd *, sec_ptr, bfd *, sec_ptr, struct bfd_link_info *); 265 /* Called to copy BFD private section data from one object file 266 to another. */ 267 bfd_boolean (*_bfd_copy_private_section_data) 268 (bfd *, sec_ptr, bfd *, sec_ptr); 269 /* Called to copy BFD private symbol data from one symbol 270 to another. */ 271 bfd_boolean (*_bfd_copy_private_symbol_data) 272 (bfd *, asymbol *, bfd *, asymbol *); 273 /* Called to copy BFD private header data from one object file 274 to another. */ 275 bfd_boolean (*_bfd_copy_private_header_data) 276 (bfd *, bfd *); 277 /* Called to set private backend flags. */ 278 bfd_boolean (*_bfd_set_private_flags) (bfd *, flagword); 279 280 /* Called to print private BFD data. */ 281 bfd_boolean (*_bfd_print_private_bfd_data) (bfd *, void *); 282 283 /* Core file entry points. */ 284#define BFD_JUMP_TABLE_CORE(NAME) \ 285 NAME##_core_file_failing_command, \ 286 NAME##_core_file_failing_signal, \ 287 NAME##_core_file_matches_executable_p, \ 288 NAME##_core_file_pid 289 290 char * (*_core_file_failing_command) (bfd *); 291 int (*_core_file_failing_signal) (bfd *); 292 bfd_boolean (*_core_file_matches_executable_p) (bfd *, bfd *); 293 int (*_core_file_pid) (bfd *); 294 295 /* Archive entry points. */ 296#define BFD_JUMP_TABLE_ARCHIVE(NAME) \ 297 NAME##_slurp_armap, \ 298 NAME##_slurp_extended_name_table, \ 299 NAME##_construct_extended_name_table, \ 300 NAME##_truncate_arname, \ 301 NAME##_write_armap, \ 302 NAME##_read_ar_hdr, \ 303 NAME##_write_ar_hdr, \ 304 NAME##_openr_next_archived_file, \ 305 NAME##_get_elt_at_index, \ 306 NAME##_generic_stat_arch_elt, \ 307 NAME##_update_armap_timestamp 308 309 bfd_boolean (*_bfd_slurp_armap) (bfd *); 310 bfd_boolean (*_bfd_slurp_extended_name_table) (bfd *); 311 bfd_boolean (*_bfd_construct_extended_name_table) 312 (bfd *, char **, bfd_size_type *, const char **); 313 void (*_bfd_truncate_arname) (bfd *, const char *, char *); 314 bfd_boolean (*write_armap) 315 (bfd *, unsigned int, struct orl *, unsigned int, int); 316 void * (*_bfd_read_ar_hdr_fn) (bfd *); 317 bfd_boolean (*_bfd_write_ar_hdr_fn) (bfd *, bfd *); 318 bfd * (*openr_next_archived_file) (bfd *, bfd *); 319#define bfd_get_elt_at_index(b,i) BFD_SEND (b, _bfd_get_elt_at_index, (b,i)) 320 bfd * (*_bfd_get_elt_at_index) (bfd *, symindex); 321 int (*_bfd_stat_arch_elt) (bfd *, struct stat *); 322 bfd_boolean (*_bfd_update_armap_timestamp) (bfd *); 323 324 /* Entry points used for symbols. */ 325#define BFD_JUMP_TABLE_SYMBOLS(NAME) \ 326 NAME##_get_symtab_upper_bound, \ 327 NAME##_canonicalize_symtab, \ 328 NAME##_make_empty_symbol, \ 329 NAME##_print_symbol, \ 330 NAME##_get_symbol_info, \ 331 NAME##_bfd_is_local_label_name, \ 332 NAME##_bfd_is_target_special_symbol, \ 333 NAME##_get_lineno, \ 334 NAME##_find_nearest_line, \ 335 _bfd_generic_find_line, \ 336 NAME##_find_inliner_info, \ 337 NAME##_bfd_make_debug_symbol, \ 338 NAME##_read_minisymbols, \ 339 NAME##_minisymbol_to_symbol 340 341 long (*_bfd_get_symtab_upper_bound) (bfd *); 342 long (*_bfd_canonicalize_symtab) 343 (bfd *, struct bfd_symbol **); 344 struct bfd_symbol * 345 (*_bfd_make_empty_symbol) (bfd *); 346 void (*_bfd_print_symbol) 347 (bfd *, void *, struct bfd_symbol *, bfd_print_symbol_type); 348#define bfd_print_symbol(b,p,s,e) BFD_SEND (b, _bfd_print_symbol, (b,p,s,e)) 349 void (*_bfd_get_symbol_info) 350 (bfd *, struct bfd_symbol *, symbol_info *); 351#define bfd_get_symbol_info(b,p,e) BFD_SEND (b, _bfd_get_symbol_info, (b,p,e)) 352 bfd_boolean (*_bfd_is_local_label_name) (bfd *, const char *); 353 bfd_boolean (*_bfd_is_target_special_symbol) (bfd *, asymbol *); 354 alent * (*_get_lineno) (bfd *, struct bfd_symbol *); 355 bfd_boolean (*_bfd_find_nearest_line) 356 (bfd *, struct bfd_section *, struct bfd_symbol **, bfd_vma, 357 const char **, const char **, unsigned int *); 358 bfd_boolean (*_bfd_find_line) 359 (bfd *, struct bfd_symbol **, struct bfd_symbol *, 360 const char **, unsigned int *); 361 bfd_boolean (*_bfd_find_inliner_info) 362 (bfd *, const char **, const char **, unsigned int *); 363 /* Back-door to allow format-aware applications to create debug symbols 364 while using BFD for everything else. Currently used by the assembler 365 when creating COFF files. */ 366 asymbol * (*_bfd_make_debug_symbol) 367 (bfd *, void *, unsigned long size); 368#define bfd_read_minisymbols(b, d, m, s) \ 369 BFD_SEND (b, _read_minisymbols, (b, d, m, s)) 370 long (*_read_minisymbols) 371 (bfd *, bfd_boolean, void **, unsigned int *); 372#define bfd_minisymbol_to_symbol(b, d, m, f) \ 373 BFD_SEND (b, _minisymbol_to_symbol, (b, d, m, f)) 374 asymbol * (*_minisymbol_to_symbol) 375 (bfd *, bfd_boolean, const void *, asymbol *); 376 377 /* Routines for relocs. */ 378#define BFD_JUMP_TABLE_RELOCS(NAME) \ 379 NAME##_get_reloc_upper_bound, \ 380 NAME##_canonicalize_reloc, \ 381 NAME##_bfd_reloc_type_lookup, \ 382 NAME##_bfd_reloc_name_lookup 383 384 long (*_get_reloc_upper_bound) (bfd *, sec_ptr); 385 long (*_bfd_canonicalize_reloc) 386 (bfd *, sec_ptr, arelent **, struct bfd_symbol **); 387 /* See documentation on reloc types. */ 388 reloc_howto_type * 389 (*reloc_type_lookup) (bfd *, bfd_reloc_code_real_type); 390 reloc_howto_type * 391 (*reloc_name_lookup) (bfd *, const char *); 392 393 394 /* Routines used when writing an object file. */ 395#define BFD_JUMP_TABLE_WRITE(NAME) \ 396 NAME##_set_arch_mach, \ 397 NAME##_set_section_contents 398 399 bfd_boolean (*_bfd_set_arch_mach) 400 (bfd *, enum bfd_architecture, unsigned long); 401 bfd_boolean (*_bfd_set_section_contents) 402 (bfd *, sec_ptr, const void *, file_ptr, bfd_size_type); 403 404 /* Routines used by the linker. */ 405#define BFD_JUMP_TABLE_LINK(NAME) \ 406 NAME##_sizeof_headers, \ 407 NAME##_bfd_get_relocated_section_contents, \ 408 NAME##_bfd_relax_section, \ 409 NAME##_bfd_link_hash_table_create, \ 410 NAME##_bfd_link_hash_table_free, \ 411 NAME##_bfd_link_add_symbols, \ 412 NAME##_bfd_link_just_syms, \ 413 NAME##_bfd_copy_link_hash_symbol_type, \ 414 NAME##_bfd_final_link, \ 415 NAME##_bfd_link_split_section, \ 416 NAME##_bfd_gc_sections, \ 417 NAME##_bfd_merge_sections, \ 418 NAME##_bfd_is_group_section, \ 419 NAME##_bfd_discard_group, \ 420 NAME##_section_already_linked, \ 421 NAME##_bfd_define_common_symbol 422 423 int (*_bfd_sizeof_headers) (bfd *, struct bfd_link_info *); 424 bfd_byte * (*_bfd_get_relocated_section_contents) 425 (bfd *, struct bfd_link_info *, struct bfd_link_order *, 426 bfd_byte *, bfd_boolean, struct bfd_symbol **); 427 428 bfd_boolean (*_bfd_relax_section) 429 (bfd *, struct bfd_section *, struct bfd_link_info *, bfd_boolean *); 430 431 /* Create a hash table for the linker. Different backends store 432 different information in this table. */ 433 struct bfd_link_hash_table * 434 (*_bfd_link_hash_table_create) (bfd *); 435 436 /* Release the memory associated with the linker hash table. */ 437 void (*_bfd_link_hash_table_free) (struct bfd_link_hash_table *); 438 439 /* Add symbols from this object file into the hash table. */ 440 bfd_boolean (*_bfd_link_add_symbols) (bfd *, struct bfd_link_info *); 441 442 /* Indicate that we are only retrieving symbol values from this section. */ 443 void (*_bfd_link_just_syms) (asection *, struct bfd_link_info *); 444 445 /* Copy the symbol type of a linker hash table entry. */ 446#define bfd_copy_link_hash_symbol_type(b, t, f) \ 447 BFD_SEND (b, _bfd_copy_link_hash_symbol_type, (b, t, f)) 448 void (*_bfd_copy_link_hash_symbol_type) 449 (bfd *, struct bfd_link_hash_entry *, struct bfd_link_hash_entry *); 450 451 /* Do a link based on the link_order structures attached to each 452 section of the BFD. */ 453 bfd_boolean (*_bfd_final_link) (bfd *, struct bfd_link_info *); 454 455 /* Should this section be split up into smaller pieces during linking. */ 456 bfd_boolean (*_bfd_link_split_section) (bfd *, struct bfd_section *); 457 458 /* Remove sections that are not referenced from the output. */ 459 bfd_boolean (*_bfd_gc_sections) (bfd *, struct bfd_link_info *); 460 461 /* Attempt to merge SEC_MERGE sections. */ 462 bfd_boolean (*_bfd_merge_sections) (bfd *, struct bfd_link_info *); 463 464 /* Is this section a member of a group? */ 465 bfd_boolean (*_bfd_is_group_section) (bfd *, const struct bfd_section *); 466 467 /* Discard members of a group. */ 468 bfd_boolean (*_bfd_discard_group) (bfd *, struct bfd_section *); 469 470 /* Check if SEC has been already linked during a reloceatable or 471 final link. */ 472 void (*_section_already_linked) (bfd *, struct bfd_section *, 473 struct bfd_link_info *); 474 475 /* Define a common symbol. */ 476 bfd_boolean (*_bfd_define_common_symbol) (bfd *, struct bfd_link_info *, 477 struct bfd_link_hash_entry *); 478 479 /* Routines to handle dynamic symbols and relocs. */ 480#define BFD_JUMP_TABLE_DYNAMIC(NAME) \ 481 NAME##_get_dynamic_symtab_upper_bound, \ 482 NAME##_canonicalize_dynamic_symtab, \ 483 NAME##_get_synthetic_symtab, \ 484 NAME##_get_dynamic_reloc_upper_bound, \ 485 NAME##_canonicalize_dynamic_reloc 486 487 /* Get the amount of memory required to hold the dynamic symbols. */ 488 long (*_bfd_get_dynamic_symtab_upper_bound) (bfd *); 489 /* Read in the dynamic symbols. */ 490 long (*_bfd_canonicalize_dynamic_symtab) 491 (bfd *, struct bfd_symbol **); 492 /* Create synthetized symbols. */ 493 long (*_bfd_get_synthetic_symtab) 494 (bfd *, long, struct bfd_symbol **, long, struct bfd_symbol **, 495 struct bfd_symbol **); 496 /* Get the amount of memory required to hold the dynamic relocs. */ 497 long (*_bfd_get_dynamic_reloc_upper_bound) (bfd *); 498 /* Read in the dynamic relocs. */ 499 long (*_bfd_canonicalize_dynamic_reloc) 500 (bfd *, arelent **, struct bfd_symbol **); 501 502@end example 503A pointer to an alternative bfd_target in case the current one is not 504satisfactory. This can happen when the target cpu supports both big 505and little endian code, and target chosen by the linker has the wrong 506endianness. The function open_output() in ld/ldlang.c uses this field 507to find an alternative output format that is suitable. 508@example 509 /* Opposite endian version of this target. */ 510 const struct bfd_target * alternative_target; 511 512 /* Data for use by back-end routines, which isn't 513 generic enough to belong in this structure. */ 514 const void *backend_data; 515 516@} bfd_target; 517 518@end example 519 520@findex bfd_set_default_target 521@subsubsection @code{bfd_set_default_target} 522@strong{Synopsis} 523@example 524bfd_boolean bfd_set_default_target (const char *name); 525@end example 526@strong{Description}@* 527Set the default target vector to use when recognizing a BFD. 528This takes the name of the target, which may be a BFD target 529name or a configuration triplet. 530 531@findex bfd_find_target 532@subsubsection @code{bfd_find_target} 533@strong{Synopsis} 534@example 535const bfd_target *bfd_find_target (const char *target_name, bfd *abfd); 536@end example 537@strong{Description}@* 538Return a pointer to the transfer vector for the object target 539named @var{target_name}. If @var{target_name} is @code{NULL}, 540choose the one in the environment variable @code{GNUTARGET}; if 541that is null or not defined, then choose the first entry in the 542target list. Passing in the string "default" or setting the 543environment variable to "default" will cause the first entry in 544the target list to be returned, and "target_defaulted" will be 545set in the BFD if @var{abfd} isn't @code{NULL}. This causes 546@code{bfd_check_format} to loop over all the targets to find the 547one that matches the file being read. 548 549@findex bfd_get_target_info 550@subsubsection @code{bfd_get_target_info} 551@strong{Synopsis} 552@example 553const bfd_target *bfd_get_target_info (const char *target_name, 554 bfd *abfd, 555 bfd_boolean *is_bigendian, 556 int *underscoring, 557 const char **def_target_arch); 558@end example 559@strong{Description}@* 560Return a pointer to the transfer vector for the object target 561named @var{target_name}. If @var{target_name} is @code{NULL}, 562choose the one in the environment variable @code{GNUTARGET}; if 563that is null or not defined, then choose the first entry in the 564target list. Passing in the string "default" or setting the 565environment variable to "default" will cause the first entry in 566the target list to be returned, and "target_defaulted" will be 567set in the BFD if @var{abfd} isn't @code{NULL}. This causes 568@code{bfd_check_format} to loop over all the targets to find the 569one that matches the file being read. 570If @var{is_bigendian} is not @code{NULL}, then set this value to target's 571endian mode. True for big-endian, FALSE for little-endian or for 572invalid target. 573If @var{underscoring} is not @code{NULL}, then set this value to target's 574underscoring mode. Zero for none-underscoring, -1 for invalid target, 575else the value of target vector's symbol underscoring. 576If @var{def_target_arch} is not @code{NULL}, then set it to the architecture 577string specified by the target_name. 578 579@findex bfd_target_list 580@subsubsection @code{bfd_target_list} 581@strong{Synopsis} 582@example 583const char ** bfd_target_list (void); 584@end example 585@strong{Description}@* 586Return a freshly malloced NULL-terminated 587vector of the names of all the valid BFD targets. Do not 588modify the names. 589 590@findex bfd_seach_for_target 591@subsubsection @code{bfd_seach_for_target} 592@strong{Synopsis} 593@example 594const bfd_target *bfd_search_for_target 595 (int (*search_func) (const bfd_target *, void *), 596 void *); 597@end example 598@strong{Description}@* 599Return a pointer to the first transfer vector in the list of 600transfer vectors maintained by BFD that produces a non-zero 601result when passed to the function @var{search_func}. The 602parameter @var{data} is passed, unexamined, to the search 603function. 604 605