package main

/*
void callStackSwitchCallbackFromThread(void);
*/
import "C"

import (
	"fmt"
	"runtime/debug"
)

func init() {
	register("StackSwitchCallback", StackSwitchCallback)
}

//export stackSwitchCallback
func stackSwitchCallback() {
	// We want to trigger a bounds check on the g0 stack. To do this, we
	// need to call a splittable function through systemstack().

#define STACK_SIZE	(64ull << 10)

static ucontext_t uctx_save, uctx_switch;

extern void stackSwitchCallback(void);

char *stack2;

static void *stackSwitchThread(void *arg) {
	// Simple test: callback works from the normal system stack.
	stackSwitchCallback();

	// Next, verify that switching stacks doesn't break callbacks.

	char *stack1 = malloc(STACK_SIZE);
	if (stack1 == NULL) {

	t.Parallel()
	switch runtime.GOOS {
	case "windows", "plan9", "android", "ios", "openbsd": // no getcontext
		t.Skipf("skipping test on %s", runtime.GOOS)
	}
	got := runTestProg(t, "testprogcgo", "StackSwitchCallback")
	skip := "SKIP\n"
	if got == skip {
		t.Skip("skipping on musl/bionic libc")
	}
	want := "OK\n"
	if got != want {
		t.Errorf("expected %q, got %v", want, got)
	}