Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

popen(): Add 'e' mode character to set close-on-exec on the new fd.

If 'e' is used, the kernel must support the recently added pipe2() system
call.

The use of pipe2() with O_CLOEXEC also fixes race conditions between
concurrent popen() calls from different threads, even if the close-on-exec
flag on the fd of the returned FILE is later cleared (because popen() closes
all file descriptors from earlier popen() calls in the child process).
Therefore, this approach should be used in all cases when pipe2() can be
assumed present.

The old version of popen() rejects "re" and "we" but treats "r+e" like "r+".

Per Regents of the University of Calfornia letter, remove advertising
clause.

# If I've done so improperly on a file, please let me know.

Sort sections.

Add or correct section number in .Xr. Use .Vt or .Fn
instead of .Xr when needed

popen() is a function, not an argument.

mdoc(7) police: Use the new .In macro for #include statements.

mdoc(7) police: use certified section headers wherever possible.

Avoid use of direct troff requests in mdoc(7) manual pages.

Introduce ".Lb" macro to libc manpages.

More libraries manpages updates following.

$Id$ -> $FreeBSD$

Add $Id$, to make it simpler for members of the translation teams to
track.

The $Id$ line is normally at the bottom of the main comment block in the
man page, separated from the rest of the manpage by an empty comment,
like so;

.\" $Id$
.\"

If the immediately preceding comment is a @(#) format ID marker than the
the $Id$ will line up underneath it with no intervening blank lines.
Otherwise, an additional blank line is inserted.

Approved by: bde

Fix a .Nm -> .Fn fix that was missed in the previous commit.

Pointed-out-by: Bruce Evans

Update manual page to reflect changes in rev 1.12 of
"src/lib/libc/gen/popen.c" --- popen() in the child
now closes any copies of popen()'ed descriptors in the parent.

Mention when bidirectional features first appeared.

Document that popen() uses a bidirectional pipe (in FreeBSD) and not a
socket pair (as in Lite2).

Merge from Lite2 (YAMFL2? :-)
Document that popen() can now create bidirectional pipes and handles.
Note that this needs to be updated since we have a native bidirectional
pipe and don't use socketpair() here.

Sort cross references.

Added missing section numbers to a bunch of .Xr macros, or
converted them into .Fn macros where appropriate. Also fixed
up some minor formatting problems.

This commit was generated by cvs2svn to compensate for changes in r1573,
which included commits to RCS files with non-trunk default branches.

BSD 4.4 Lite Lib Sources