关于C#：pthread_join函数在执行后杀死线程，还是我们需要调用pthread_cancel / pthread_exit？

pthread_join function kill the thread after execution or we need to call pthread_cancel/pthread_exit?

pthread_join()函数在执行后杀死线程，或者我们需要调用pthread_cancel() / pthread_exit()？

我正在调用pthread_cancel() / pthread_kill()，该函数返回3，即没有附加带有thread_id的线程。

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#include <stdio.h>
#include <pthread.h>
#include <unistd.h>
#include <signal.h>

void * run (void *);

int main() {
pthread_t p1, p2;
int a = 9;
printf("%d\
", pthread_create(&p1, NULL, &run, (void*)&p1));
printf("%d\
", pthread_create(&p2, NULL, &run, (void*)&p2));

printf("%d\
", pthread_join(p1, NULL));
//usleep(1000);
printf("%d\
", pthread_join(p2, NULL));

printf("before exit\
");
printf("%d\
", pthread_cancel(p1));
printf("after exit\
");
printf("%d\
", pthread_cancel(p2));
printf("both thread exited\
");

printf("%d\
", pthread_join(p1, NULL));
printf("%d\
", pthread_join(p2, NULL));
printf("terminated\
");

printf("%d\
", pthread_kill(p1, 0));
printf("%d\
", pthread_kill(p2, 0));
printf("ext\
");

printf("%d\
", pthread_join(p1, NULL));
printf("%d\
", pthread_join(p2, NULL));
printf("jion\
");

return 0;
}

void *run (void *p) {

int *i = (int*)p;
printf("created i = %d\
", *i);
}

这是我正在使用的代码。在此pthread_cancel区域中，所有函数返回3，这意味着线程已被杀死。

相关讨论

有些上下文会很好...但是如果您只是在等待线程(大概只有一个您关心的线程)终止/返回，那么pthread_join就足够了。

The pthread_join() function waits for the thread specified by thread
to terminate. If that thread has already terminated, then pthread_join() returns
immediately.

http://www.kernel.org/doc/man-pages/online/pages/man3/pthread_join.3.html

检查手册页上的用法/警告。

在pthread_join()之后添加

1 2	/* Last thing that main() should do */ pthread_exit(NULL);

有关更多详细信息，请参见此处。

pthread_join()用于使main()线程等待，直到所有线程完成其执行。当特定线程完成它的执行时，控制权到达pthread_join()。
因此，如果您尝试取消/杀死该特定线程，将返回错误。

样品代号

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#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#define NUM_THREADS 4

void *BusyWork(void *t)
{
int i;
long tid;
tid = (long)t;
printf("Thread %ld starting...\
",tid);
pthread_exit((void*) t); //Exits that current thread.
}

int main (int argc, char *argv[])
{
pthread_t thread[NUM_THREADS];
int rc;
long t;
void *status;

for(t=0; t<NUM_THREADS; t++) {
printf("Main: creating thread %ld\
", t);
rc = pthread_create(&thread[t], NULL, BusyWork, (void *)t);
if (rc) {
printf("ERROR; return code from pthread_create() is %d\
", rc);
exit(-1);
}
}

/* Wait for completion */
for(t=0; t<NUM_THREADS; t++) {
rc = pthread_join(thread[t], &status);
if (rc) {
printf("ERROR; return code from pthread_join() is %d\
", rc);
exit(-1);
}
printf("Main: completed join with thread %ld having a status of %ld\
",t,(long)status);
}

printf("Main: program completed. Exiting.\
");
pthread_exit(NULL); // Exits main thread.
}

对于@Joachim Pileborg

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#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#define NUM_THREADS 4

void *BusyWork(void *t)
{
int i;
long tid;
tid = (long)t;

printf("Thread %ld starting...\
",tid);

for(i = 0; i <10000000; i++)
printf("\
Thread: %ld, %d", tid, i);

pthread_exit((void*) t); //Exits that current thread.
}

int main (int argc, char *argv[])
{
pthread_t thread[NUM_THREADS];
int rc;
long t;
void *status;

for(t=0; t<NUM_THREADS; t++) {
printf("Main: creating thread %ld\
", t);
rc = pthread_create(&thread[t], NULL, BusyWork, (void *)t);
if (rc) {
printf("ERROR; return code from pthread_create() is %d\
", rc);
exit(-1);
}
}

//printf("Main: program completed. Exiting.\
");
pthread_exit(NULL); // Exits main thread(work will be done).
//return 0;//( Threads will exit once main exits.)
}