setenv
======

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

Gnulib module: setenv

Portability problems fixed by Gnulib:

  * This function is missing on some platforms: AIX 4.3.2, HP-UX 11.23, IRIX 6.5, Solaris 9, mingw, BeOS.

  * This function is not declared on some platforms: OSF/1 5.1.

  * On some platforms, this function does not fail with EINVAL when passed an empty string or a string containing =: MacOS X 10.5, FreeBSD 6.0, NetBSD 1.6, OpenBSD 3.8, Cygwin 1.5.x.

  * On some platforms, this function removes a leading = from the value argument: Cygwin 1.5.x.

Portability problems not fixed by Gnulib:

  * Older versions of POSIX required that setenv(NULL,"",0) gracefully fail with EINVAL, but not all implementations guarantee this, and the requirement was removed.