+#ifdef HAS_SIGPROCMASK
+ /* From sigaction(2) (FreeBSD man page):
+ * | Signal routines normally execute with the signal that
+ * | caused their invocation blocked, but other signals may
+ * | yet occur.
+ * Emulation of this behavior (from within Perl) is enabled
+ * using sigprocmask
+ */
+ int was_blocked;
+ sigset_t newset, oldset;
+
+ sigemptyset(&newset);
+ sigaddset(&newset, sig);
+ sigprocmask(SIG_BLOCK, &newset, &oldset);
+ was_blocked = sigismember(&oldset, sig);
+ if (!was_blocked) {
+ SV* save_sv = newSVpvn((char *)(&newset), sizeof(sigset_t));
+ ENTER;
+ SAVEFREESV(save_sv);
+ SAVEDESTRUCTOR_X(unblock_sigmask, SvPV_nolen(save_sv));
+ }
+#endif