我是 Mac 编程新手,我对 Grand Central Dispatch 感到非常惊讶。我读到了它,看起来像是并行编程的完美解决方案。我使用 POSIX 线程并想转移到 GCD。
我在 Apple Developer Connection 中看到了示例代码,但它让我很困惑。我搜索了一个包含两个线程的简单示例,但找不到。
如何使用 GCD 编写此示例代码???
#include <stdio.h> /* standard I/O routines */
#include <pthread.h> /* pthread functions and data structures */
/* function to be executed by the new thread */
void* do_loop(void* data)
{
int i; /* counter, to print numbers */
int j; /* counter, for delay */
int me = *((int*)data); /* thread identifying number */
for (i=0; i<10; i++)
{
for (j=0; j<500000; j++) /* delay loop */
;
printf("'%d' - Got '%d'\n", me, i);
}
/* terminate the thread */
pthread_exit(NULL);
}
void* th2(void* data)
{
cout << "Thread nº 2" << endl;
}
int main(int argc, char* argv[])
{
int thr_id; /* thread ID for the newly created thread */
pthread_t p_thread1;
pthread_t p_thread2; /* thread's structure */
int a = 1; /* thread 1 identifying number */
int b = 2; /* thread 2 identifying number */
/* create a new thread that will execute 'do_loop()' */
thr_id = pthread_create(&p_thread1, NULL, do_loop, (void*)&a);
/* run 'do_loop()' in the main thread as well */
thr_id = pthread_create(&p_thread2, NULL, th2, (void*)&b);
return 0;
}
提前致谢
最佳答案
应该是这样的:
// The block replaces your doLoop function, it basically does the same thing
dispatch_block_t myBlock = ^{
int i; /* counter, to print numbers */
int j; /* counter, for delay */
dispatch_queue_t me = dispatch_get_current_queue(); /* The queue which currently runs this block */
for (i=0; i<10; i++)
{
for (j=0; j<500000; j++) /* delay loop */
;
printf("'%s' - Got '%d'\n", dispatch_queue_get_label(me), i); // Print the name of the queue
}
};
// Create two queues
dispatch_queue_t queue1 = dispatch_queue_create("my.totally.unique.and.reverse.dns.identifier.1", NULL);
dispatch_queue_t queue2 = dispatch_queue_create("my.totally.unique.and.reverse.dns.identifier.2", NULL);
// Let both execute the block
dispatch_async(queue1, myBlock);
dispatch_async(queue2, myBlock);
// And then release the queues because we are great citizens who care about memory
dispatch_release(queue1);
dispatch_release(queue2);
关于objective-c - Grand Central Dispatch 的简单示例,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/5502906/