diff --git a/include/signal.h b/include/signal.h
index 5f39ddbd..9cebddd9 100644
--- a/include/signal.h
+++ b/include/signal.h
@@ -106,6 +106,7 @@ void (*sigset(int, void (*)(int)))(int);
 #ifdef _GNU_SOURCE
 typedef void (*sighandler_t)(int);
 void (*bsd_signal(int, void (*)(int)))(int);
+int sigisemptyset(const sigset_t *);
 #define SA_NOMASK SA_NODEFER
 #endif
 
diff --git a/src/signal/sigisemptyset.c b/src/signal/sigisemptyset.c
new file mode 100644
index 00000000..e2410514
--- /dev/null
+++ b/src/signal/sigisemptyset.c
@@ -0,0 +1,9 @@
+#define _GNU_SOURCE
+#include <signal.h>
+#include <string.h>
+
+int sigisemptyset(const sigset_t *set)
+{
+	static const sigset_t zeroset;
+	return !memcmp(set, &zeroset, 8);
+}