我在dispatch_semaphore_dispose上收到EXC_BAD_指令(代码=EXC_I386_INVOP，子代码=0x0)，但我真的不知道如何追踪这一问题的根本原因.我的代码使用了dispatch\u async、dispatch\u group\u enter等等.
更新:
代码:
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0);
dispatch_group_t group = dispatch_group_create();
for (...) {
if (...) {
dispatch_group_enter(group);
dispatch_async(queue, ^{
[self webserviceCall:url onCompletion:^{
dispatch_group_leave(group);
}];
});
}
}
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
dispatch_group_wait(group, dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2.0 * NSEC_PER_SEC)));
dispatch_sync(queue, ^{
// call completion handler passed in by caller
});
});