1 files changed, 38 insertions, 0 deletions
diff --git a/src/stdlib/atexit.c b/src/stdlib/atexit.c
new file mode 100644
index 00000000..180dc5e2
--- /dev/null
+++ b/src/stdlib/atexit.c
@@ -0,0 +1,38 @@
+#include <stdlib.h>
+#include "errno.h"
+#include "nonstd/internal.h"
+
+/** register a function to run at program exit **/
+
+int atexit(void (*func)(void))
+{
+	struct atexit *ae = __libc(ATEXIT);
+	while (ae->nfns == sizeof(ae->fns) / sizeof(ae->fns[0])) {
+		if (ae->next == NULL) {
+			ae->next = calloc(1, sizeof(*ae->next));
+			if (ae->next == NULL) {
+				#ifdef ENOMEM
+				errno =	ENOMEM;
+				#endif
+				return 1;
+			}
+			ae->next->prev = ae;
+		}
+		ae = ae->next;
+	}
+	ae->fns[ae->nfns++] = func;
+	return 0;
+}
+
+/***
+registers the function ARGUMENT(func) to be called when the program
+exits normally by calling FUNCTION(exit) or returning from FUNCTION(main). The
+function must take no parameters and return no value.
+***/
+
+/*
+IMPLEMENTATION(The number of registrations allowed (at least 32))
+RETURN_FAILURE(NONZERO)
+RETURN_SUCCESS(0)
+STDC(1)
+*/