1 files changed, 58 insertions, 0 deletions
diff --git a/config/auto-aux/signals.c b/config/auto-aux/signals.c
new file mode 100644
index 000000000..c355545d8
--- /dev/null
+++ b/config/auto-aux/signals.c
@@ -0,0 +1,58 @@
+/* To determine the semantics of signal handlers
+   (System V: signal is reset to default behavior on entrance to the handler
+    BSD: signal handler remains active). */
+
+#include <stdio.h>
+#include <signal.h>
+
+/* Find a signal that is ignored by default */
+
+#ifdef SIGCHLD
+#define IGNSIG SIGCHLD
+#else
+#ifdef SIGIO
+#define IGNSIG SIGIO
+#else
+#ifdef SIGCLD
+#define IGNSIG SIGCLD
+#else
+#ifdef SIGPWR
+#define IGNSIG SIGPWR
+#endif
+#endif
+#endif
+#endif
+
+#ifdef IGNSIG
+
+int counter;
+
+void sig_handler(dummy)
+     int dummy;
+{
+  counter++;
+}
+
+int main(argc, argv)
+     int argc;
+     char ** argv;
+{
+  signal(IGNSIG, sig_handler);
+  counter = 0;
+  kill(getpid(), IGNSIG);
+  kill(getpid(), IGNSIG);
+  return (counter == 2 ? 0 : 1);
+}
+
+#else
+
+/* If no suitable signal was found, assume System V */
+
+int main(argc, argv)
+     int argc;
+     char ** argv;
+{
+  return 1;
+}
+
+#endif