vwprintf
========

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

Gnulib module: ---

Portability problems fixed by Gnulib:

Portability problems not fixed by Gnulib:

  * This function is missing on some platforms: NetBSD 3.0, OpenBSD 3.8, Minix 3.1.8, HP-UX 11.00, IRIX 6.5, Solaris 2.6, Cygwin 1.5.x, Interix 3.5, BeOS, Cygwin 1.7.

  * This function exists, but does not support wide arguments on some platforms: Cygwin 1.5.x.

  * On AIX and Windows platforms, wchar_t is a 16-bit type and therefore cannot accommodate all Unicode characters.

  * When formatting an integer with grouping flag, this function inserts thousands separators even in the "C" locale on some platforms: NetBSD 5.1.

  * On some platforms, this function does not set errno or the stream error indicator on attempts to write to a read-only stream: Cygwin 1.7.9.