+@item
+@code{volatile sig_atomic_t} is rejected by older compilers on some
+platforms:
+AIX.
+@item
+@code{sigset_t} is missing on some platforms:
+MSVC 9.
+@item
+@code{sigset_t} is only declared in <sys/types.h> on some platforms:
+mingw.
+@item
+@code{struct sigaction} and @code{siginfo_t} are missing on some
+platforms:
+mingw, MSVC 9.
+@item
+@code{struct sigaction} lacks the @code{sa_sigaction} member on some
+platforms:
+Irix 5.3, Interix 3.5.
+@item
+The type @code{pid_t} is not defined on some platforms:
+MSVC 9.
+@item
+The signal @code{SIGPIPE} is not defined on some platforms:
+mingw, MSVC 9.
+@item
+The macro @code{SA_NODEFER} is not defined on some platforms:
+Interix 3.5.
+@item
+The macros @code{SA_RESETHAND} and @code{SA_RESTART} are not defined
+on some platforms:
+NonStop.
+@item
+The type @code{sighandler_t} (a GNU extension) is not defined on most non-glibc
+platforms:
+MacOS X 10.5, FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, AIX 5.1, HP-UX 11,
+IRIX 6.5, OSF/1 5.1, Solaris 11 2011-11, Cygwin, mingw, MSVC 9, Interix 3.5, BeOS.