[英]APR threads and signal handling
I am currently trying to implement threads using the Apache Portable Runtime. 我目前正在尝试使用Apache Portable Runtime实现线程。 Everything works fine, except I am not really sure if I am doing it the way it's intended to do due to lack of documentation or examples.
一切正常,除非我不确定我是否按照预期的方式进行操作,因为缺少文档或示例。
I need two threads and signal handling to catch a CTRL-C on the console to cleanup my server and possibly the threads. 我需要两个线程和信号处理来捕获控制台上的CTRL-C来清理我的服务器和可能的线程。 This is my current approach:
这是我目前的做法:
// Define APR thread pool
apr_pool_t *pool;
// Define server
MyServer *server;
// Define threads
apr_thread_t *a_thread, *b_thread;
apr_status_t status;
static void * APR_THREAD_FUNC func_a(apr_thread_t * thread,
void *data) {
// do func_a stuff here
}
static void * APR_THREAD_FUNC func_b(apr_thread_t * thread,
void *data) {
// do func_b stuff here
}
// Cleanup before exit
void cleanup(int s) {
printf("Caught signal %d\n", s);
// Destroy thread pool
apr_pool_destroy(pool);
//apr_thread_exit(a_thread, APR_SUCCESS);
//apr_thread_exit(b_thread, APR_SUCCESS);
//apr_terminate();
// Stop server and cleanup
server->stopServer();
delete server;
exit(EXIT_SUCCESS);
}
int main(void) {
// Signal handling
signal(SIGINT, cleanup);
// Create server
server = MyServerFactory::getServerImpl();
bool success = server->startServer();
// Initialize APR
if (apr_initialize() != APR_SUCCESS) {
printf("Could not initialize\n");
return EXIT_FAILURE;
}
// Create thread pool
if (apr_pool_create(&pool, NULL) != APR_SUCCESS) {
printf("Could not allocate pool\n");
return EXIT_FAILURE;
}
// Create a_thread thread
if (apr_thread_create(&a_thread, NULL, func_a, NULL,
pool) != APR_SUCCESS) {
printf("Could not create a_thread\n");
return EXIT_FAILURE;
}
//Create b_thread thread
if (apr_thread_create(&b_thread, NULL, func_b, NULL,
pool) != APR_SUCCESS) {
printf("Could not create b_thread\n");
return EXIT_FAILURE;
}
// Join APR threads
apr_thread_join(&status, a_thread);
apr_thread_join(&status, b_thread);
return EXIT_SUCCESS;
}
This works more or less as expected. 这或多或少按预期工作。 The only thing I am not really sure about is if the cleanup works fine.
我唯一不确定的是清理是否正常。
The cleanup-function seems to be called more then one time (String "Caught signal.." appears more than one time on terminal). 清理功能似乎被多次调用(字符串“Caught signal ..”在终端上出现多次)。 Is there a way to prevent this?
有办法防止这种情况吗? Is this problematic?
这有问题吗?
I found more than one example for cleaning up APR threads after usage. 我发现在使用后清理APR线程的例子不止一个。 Is my way sufficient or do I need some of the commented stuff?
我的方式是否足够,还是需要一些注释的东西? Or am I completely wrong?
还是我完全错了?
APR thread cleanup is explained in decent detail in the threading section of the APR Tutorial . 在APR教程的线程部分中详细解释了APR线程清理。 In order, the cleanup steps look like this:
按顺序,清理步骤如下所示:
apr_thread_exit()
in the thread itself . apr_thread_exit()
。 While Unix threads terminate automatically, Windows threads do not. apr_thread_join()
in the main thread to wait for the termination of all threads. apr_thread_join()
以等待所有线程的终止。 apr_pool_destroy()
to free the main memory pool. apr_pool_destroy()
以释放主内存池。 (Child memory pools are freed with apr_thread_exit()
.) apr_thread_exit()
释放子内存池。) apr_terminate()
to release other resources (sockets, etc.). apr_terminate()
以释放其他资源(套接字等)。 Note that simply calling exit()
in another thread without these final steps can cause crashes . exit()
会导致崩溃 。 They also have a brief sample program that demonstrates some of this stuff. 他们还有一个简短的示例程序 ,演示了一些这样的东西。
As for why your signal handler is firing twice, I don't think that has to do with APR. 至于你的信号处理程序发射两次的原因,我不认为这与APR有关。 SIGINT is sent to parent and child processes, so I suspect
MyServer
is forking a new process and both are invoking the handler. SIGINT被发送到父进程和子进程,所以我怀疑
MyServer
正在分支一个新进程并且都在调用处理程序。
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