1 // RUN: %clang_tsan %s -o %t -undefined dynamic_lookup
2 // RUN: %run %t 2>&1 | FileCheck %s --implicit-check-not='ThreadSanitizer'
3
4 #include "dispatch/dispatch.h"
5
6 #include <stdio.h>
7
8 // Allow compilation with pre-macOS 10.14 (and aligned) SDKs
9 API_AVAILABLE(macos(10.14), ios(12.0), tvos(12.0), watchos(5.0))
10 DISPATCH_EXPORT DISPATCH_NONNULL_ALL DISPATCH_NOTHROW
11 void dispatch_async_and_wait(dispatch_queue_t queue,
12 DISPATCH_NOESCAPE dispatch_block_t block);
13
14 long global;
15
main()16 int main() {
17 // Guard execution on pre-macOS 10.14 (and aligned) platforms
18 if (dispatch_async_and_wait == NULL) {
19 fprintf(stderr, "Done.\n");
20 return 0;
21 }
22
23 dispatch_queue_t q = dispatch_queue_create("my.queue", DISPATCH_QUEUE_SERIAL);
24 dispatch_semaphore_t s = dispatch_semaphore_create(0);
25
26 // Force queue to context switch onto separate thread.
27 dispatch_async(q, ^{
28 dispatch_semaphore_wait(s, DISPATCH_TIME_FOREVER);
29 });
30 dispatch_semaphore_signal(s);
31
32 global++;
33 dispatch_async_and_wait(q, ^{
34 // The queue continues to execute on separate thread. This would cause a
35 // race if we had used `dispatch_async()` without the `_and_wait` part.
36 global++;
37 });
38 global++;
39
40 fprintf(stderr, "Done.\n");
41 return 0;
42 }
43
44 // CHECK: Done.
45