glibc 2.3.6, MacOS X 10.3, FreeBSD 6.0, NetBSD 3.0, OpenBSD 3.8, AIX
5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 8, Cygwin 1.5.x, mingw,
Interix 3.5, BeOS.
+But the replacement function is not safe to be used in libraries and is not multithread-safe.
@end itemize
Portability problems not fixed by Gnulib: