@itemize
@item
This function is missing on some platforms:
-Solaris 2.4, mingw, BeOS.
+Minix 3.1.8, Solaris 2.4, mingw, MSVC 9, BeOS.
@item
This function is declared in @code{<pthread.h>} instead of @code{<signal.h>}
on some platforms:
-MacOS X 10.3, FreeBSD 6.4, OpenBSD 3.8, OSF/1 4.0, Solaris 2.6.
+Mac OS X 10.3, FreeBSD 6.4, OpenBSD 3.8, OSF/1 4.0, Solaris 2.6.
+@item
+This function does nothing and always returns 0 in programs that are not
+linked with @code{-lpthread} on some platforms:
+FreeBSD 6.4, HP-UX 11.31, Solaris 9.
+@item
+When it fails, this functions returns @minus{}1 instead of the error number on
+some platforms:
+Cygwin 1.7.5.
+@item
+This function does not immediately raise signals that were pending before
+the call and unblocked by the call on some platforms:
+IRIX 6.5.
@end itemize
Portability problems not fixed by Gnulib: