function fails to leave a NUL-terminated string in the buffer on some
platforms:
glibc 2.13, FreeBSD 8.2, Solaris 10.
+@item
+When the value is out of range but the buffer is too small, this
+function does not always return the longest possible string on some
+platforms:
+OpenBSD 4.7.
@end itemize
Portability problems not fixed by Gnulib: