1 files changed, 12 insertions, 0 deletions
diff --git a/src/signal/sigismember.c b/src/signal/sigismember.c
new file mode 100644
index 00000000..afd29e52
--- /dev/null
+++ b/src/signal/sigismember.c
@@ -0,0 +1,12 @@
+#include <signal.h>
+#include <errno.h>
+
+int sigismember(const sigset_t *set, int sig)
+{
+	unsigned s = sig-1;
+	if (s >= 8*sizeof(sigset_t)) {
+		errno = EINVAL;
+		return -1;
+	}
+	return !!(set->__bits[s/8/sizeof *set->__bits] & 1UL<<(s&8*sizeof *set->__bits-1));
+}