dup2
====

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

Gnulib module: dup2

Portability problems fixed by Gnulib:

  * This function always returns 0 for success on some platforms: mingw.

  * This function can hang when duplicating an fd to itself on some platforms: mingw.

  * 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.

  * This function is missing on some older platforms.

Portability problems not fixed by Gnulib: