--- /dev/null
+++ Libc/Libc-1698.140.3/tests/quick_exit.c
@@ -0,0 +1,65 @@
+#include <sys/wait.h>
+
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <darwintest.h>
+
+T_GLOBAL_META(T_META_RUN_CONCURRENTLY(true));
+
+static void func_a(void)
+{
+	if (write(STDOUT_FILENO, "a", 1) != 1)
+		_Exit(1);
+}
+
+static void func_b(void)
+{
+	if (write(STDOUT_FILENO, "b", 1) != 1)
+		_Exit(1);
+}
+
+static void func_c(void)
+{
+	if (write(STDOUT_FILENO, "c", 1) != 1)
+		_Exit(1);
+}
+
+static void child(void)
+{
+	// this will be received by the parent
+	printf("hello, ");
+	fflush(stdout);
+	// this won't, because quick_exit() does not flush
+	printf("world");
+	// these will be called in reverse order, producing "abc"
+	if (at_quick_exit(func_c) != 0 ||
+	    at_quick_exit(func_b) != 0 ||
+	    at_quick_exit(func_a) != 0)
+		_Exit(1);
+	quick_exit(0);
+}
+
+T_DECL(quick_exit, "Test quick_exit and at_quick_exit")
+{
+	char buf[100] = "";
+	ssize_t len;
+	int p[2], wstatus = 0;
+	pid_t pid;
+
+	T_ASSERT_POSIX_SUCCESS(pipe(p), NULL);
+	pid = fork();
+	if (pid == 0) {
+		if (dup2(p[1], STDOUT_FILENO) < 0)
+			_Exit(1);
+		(void)close(p[1]);
+		(void)close(p[0]);
+		child();
+		_Exit(1);
+	}
+	T_ASSERT_POSIX_SUCCESS(pid, "expect fork() to succeed");
+	T_EXPECT_EQ(waitpid(pid, &wstatus, 0), pid, "expect to collect child process");
+	T_EXPECT_EQ(wstatus, 0, "expect child to exit cleanly");
+	T_EXPECT_POSIX_SUCCESS(len = read(p[0], buf, sizeof(buf)), NULL);
+	T_EXPECT_EQ_STR(buf, "hello, abc", NULL);
+}