- r = read(signal_pipe[0], &s, sizeof(s));
- if (r == sizeof(s)) {
- PARA_DEBUG_LOG("next signal: %d\n", s);
- return s;
+/**
+ * Unblock a signal.
+ *
+ * \param sig The signal to unblock.
+ *
+ * This function removes the given signal from the current set of blocked
+ * signals.
+ *
+ * \sa \ref para_block_signal(), sigprocmask(2), sigaddset(3).
+ */
+void para_unblock_signal(int sig)
+{
+ sigset_t set;
+
+ PARA_DEBUG_LOG("unblocking signal %d\n", sig);
+ sigemptyset(&set);
+ sigaddset(&set, sig);
+ sigprocmask(SIG_UNBLOCK, &set, NULL);
+}
+
+/**
+ * Return the number of the next pending signal.
+ *
+ * \param rfds The fd_set containing the signal pipe.
+ *
+ * \return On success, the number of the received signal is returned. If there
+ * is no signal currently pending, the function returns zero. On read errors
+ * from the signal pipe, the process is terminated.
+ */
+int para_next_signal(fd_set *rfds)
+{
+ size_t n;
+ int s, ret = read_nonblock(signal_pipe[0], &s, sizeof(s), rfds, &n);
+
+ if (ret < 0) {
+ PARA_EMERG_LOG("%s\n", para_strerror(-ret));
+ exit(EXIT_FAILURE);