9.191 dup2

POSIX specification:
http://www.opengroup.org/onlinepubs/9699919799/functions/dup2.html

Gnulib module: dup2 or dup2-obsolete

Portability problems fixed by either Gnulib module dup2 or dup2-obsolete:

• This function always returns 0 for success on some platforms: mingw, MSVC 9.
• This function can hang when duplicating an fd to itself on some platforms: mingw, MSVC 9.
• This function crashes when invoked with invalid arguments on some platforms: Cygwin 1.7.17, MSVC 9.
• This function resets the FD_CLOEXEC flag when duplicating an fd to itself on some platforms: Haiku.
• This function returns 0 for dup2 (1, 1) on some platforms: Cygwin 1.5.x.
• This function may return -EBADF instead of -1 on some platforms: Linux releases between July 2008 and May 2009 (versions 2.6.27 to 2.6.29).
• This function returns EMFILE instead of EBADF for extremely large targets, which interferes with using dup2(fd,fd)==fd) as the minimal EBADF filter: FreeBSD 6.1, Cygwin 1.5.

Portability problems fixed by Gnulib module dup2-obsolete:

• This function is missing on some older platforms.

Portability problems not fixed by Gnulib: