--- /dev/null
+++ Libc/Libc-1583.60.2/tests/custom_pcs_func.c
@@ -0,0 +1,25 @@
+#include <darwintest.h>
+#include <execinfo.h>
+#include <libc_private.h>
+
+#define MAGIC ((void *)0xdeadbeef)
+
+static void custom_thread_stack_pcs(vm_address_t *buffer, unsigned max,
+               unsigned *nb, __unused unsigned skip, __unused void *startfp) {
+	T_EXPECT_GE(max, 1, "need to be allowed to write at least one address for this test to be sane");
+
+	buffer[0] = (vm_address_t)MAGIC;
+	*nb = 1;
+}
+
+T_DECL(custom_pcs_func, "make sure backtrace respects custom get pcs functions")
+{
+	backtrace_set_pcs_func(custom_thread_stack_pcs);
+
+	void *array[2] = { NULL, NULL };
+	int nframes = backtrace(array, 2);
+	T_EXPECT_EQ(nframes, 1, "custom_thread_stack_pcs should only find one pc");
+
+	T_EXPECT_EQ(array[1], NULL, "the second pc should not be written");
+	T_EXPECT_EQ(array[0], MAGIC, "the first pc magic should be %p", MAGIC);
+}