分离的pthread会导致内存泄漏

当使用未分离的pthreads终止进程时,存在已知的内存泄漏.但是,分离线程似乎不是一个解决方案.请考虑以下最小示例:

#include 
#include 

static void* thread(void* _) {
  for(;;); return NULL;
}

int main(void) {
  pthread_attr_t attr; 
  pthread_attr_init(&attr);
  pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
  pthread_t tid; pthread_create(&tid, &attr, thread, NULL);
  pthread_attr_destroy(&attr);
  return 0;
}

创建具有无限循环的分离线程,并立即终止该过程.根据pthread_detach(3),一旦整个过程终止,线程的资源应该自动释放回系统.然而,这显然不是正在发生的事情:

gcc -pthread c.c
valgrind --leak-check=full a.out

==9341== Command: a.out
==9341==
==9341==
==9341== HEAP SUMMARY:
==9341==     in use at exit: 272 bytes in 1 blocks
==9341==   total heap usage: 1 allocs, 0 frees, 272 bytes allocated
==9341==
==9341== 272 bytes in 1 blocks are possibly lost in loss record 1 of 1
==9341==    at 0x4C2ABB4: calloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==9341==    by 0x4012598: _dl_allocate_tls (dl-tls.c:296)
==9341==    by 0x4E3C7B5: pthread_create@@GLIBC_2.2.5 (allocatestack.c:579)
==9341==    by 0x400825: main (in /home/witiko/a.out)
==9341==
==9341== LEAK SUMMARY:
==9341==    definitely lost: 0 bytes in 0 blocks
==9341==    indirectly lost: 0 bytes in 0 blocks
==9341==      possibly lost: 272 bytes in 1 blocks
==9341==    still reachable: 0 bytes in 0 blocks
==9341==         suppressed: 0 bytes in 0 blocks

我应该担心吗？在实际的程序中,我有几个阻塞线程,所以,就像在最小的例子中,我不能真正pthread_join()使用它们.我应该打电话pthread_cancel()而不是exit()直接打电话吗？