view doc/posix-functions/dup2.texi @ 17243:b0688a78cfaf

dup2: work around cygwin bug Detected by './gnulib-tool --test dup2 cloexec'. Reported upstream: http://cygwin.com/ml/cygwin/2012-12/msg00377.html and fixed already: http://cygwin.com/ml/cygwin-cvs/2012-q4/msg00202.html but as we want to work with older cygwin, we'll have to carry this in gnulib for a while. * m4/dup2.m4 (gl_FUNC_DUP2): Flush out cygwin core dump. * lib/dup2.c (rpl_dup2): Work around it. * doc/posix-functions/dup2.texi (dup2): Document it. Signed-off-by: Eric Blake <eblake@redhat.com>
author Eric Blake <eblake@redhat.com>
date Mon, 31 Dec 2012 11:15:53 -0700
parents b0c5a211d6fe
children
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@node dup2
@section @code{dup2}
@findex dup2

POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/dup2.html}

Gnulib module: dup2 or dup2-obsolete

Portability problems fixed by either Gnulib module @code{dup2} or @code{dup2-obsolete}:
@itemize
@item
This function always returns 0 for success on some platforms:
mingw, MSVC 9.

@item
This function can hang when duplicating an fd to itself on some platforms:
mingw, MSVC 9.

@item
This function crashes when invoked with invalid arguments on some platforms:
Cygwin 1.7.17, MSVC 9.

@item
This function resets the @code{FD_CLOEXEC} flag when duplicating an fd
to itself on some platforms:
Haiku.

@item
This function returns 0 for @code{dup2 (1, 1)} on some platforms:
Cygwin 1.5.x.

@item
This function may return @code{-EBADF} instead of @code{-1} on some platforms:
Linux releases between July 2008 and May 2009 (versions 2.6.27 to 2.6.29).

@item
This function returns @code{EMFILE} instead of @code{EBADF} for
extremely large targets, which interferes with using
@code{dup2(fd,fd)==fd)} as the minimal @code{EBADF} filter:
FreeBSD 6.1, Cygwin 1.5.
@end itemize

Portability problems fixed by Gnulib module @code{dup2-obsolete}:
@itemize
@item
This function is missing on some older platforms.
@end itemize

Portability problems not fixed by Gnulib:
@itemize
@end itemize