strerror_r
==========

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

Gnulib module: strerror_r-posix

Portability problems fixed by Gnulib:

  * This function is missing on some platforms: NetBSD 3.0, HP-UX 11.23, IRIX 6.5, Solaris 9, mingw.

  * glibc and Cygwin have an incompatible version of this function.  The POSIX compliant code

          char *s = (strerror_r (err, buf, buflen) == 0 ? buf : NULL);

     is essentially equivalent to this code using the glibc function:

          char *s = strerror_r (err, buf, buflen);

  * This function is sometimes not declared in <string.h> on some platforms: glibc 2.8, OSF/1 5.1.

  * The third argument is of type int instead of size_t on some platforms: AIX 5.1, OSF/1 5.1.

  * When this function fails, it returns -1 and sets errno, instead of returning the error number, on some platforms: glibc 2.12 with -D_POSIX_C_SOURCE=200112L, AIX 6.1, OSF/1 5.1.

  * This function does not support the error values that are specified by POSIX but not defined by the system, on some platforms: OpenBSD 4.0, OSF/1 5.1, NonStop Kernel, Cygwin 1.5.x.

  * This function reports failure for strerror_r(0, buf, len), although POSIX requires this to succeed, on some platforms: FreeBSD 8.2

  * This function always fails when the third argument is less than 80 on some platforms: HP-UX 11.31.

  * When the buffer is too small, this function does not fail, but instead truncates the result and returns 0 on some platforms: OSF/1 5.1.

Portability problems not fixed by Gnulib:

  * When the buffer is too small, this function does not fail, but instead truncates the result and returns 0 on some platforms: AIX 6.1.