Question

我正在创建一个服务器，每次客户端连接到服务器时都会创建一个分离的线程。

    TRACE(DETAILED_TRACE,("Entered infinite loop of server.\n"));
    printf("\nThread counter = %d\n", thread_counter);
    printf("Waiting for connection...\n");

    len=sizeof(cliaddr);

    connfd=accept(sd,(struct sockaddr*)&cliaddr,&len);
    if (connfd < 0)
    {
        if (errno == EINTR)
            printf("Interrupted system call ??");
        else
            error_exit(SYSTEM_ERROR, "Connection");
    }
    if(FLAG_UNSET == server_stop_flag)
    {
        printf("Connection from %s\n",
               inet_ntop(AF_INET,&cliaddr.sin_addr,buf,sizeof(buf)));

        thread_return = pthread_create((th+thread_counter), NULL
                                       ,thread_func,(void*)&connfd);
        if(thread_return)
        {
            error_exit(SYSTEM_ERROR, "Thread Creation");
        }
        else
        {
            thread_return = pthread_detach(th[thread_counter
                                               ]);
            if(thread_return)
            {
                printf("\nError code: %d\n", thread_retu
                       rn);
                error_exit(SYSTEM_ERROR, "Detatch error"
                    );
            }
        }
        thread_counter++;
        thread_counter = thread_counter%MAX_THREADS;

在运行valgrind时，我一直这样做：

===================================================================
16 bytes in 1 blocks are still reachable in loss record 1 of 2
   at 0x1B905301: calloc (vg_replace_malloc.c:176)
   by 0x9E7364: _dlerror_run (in /lib/libdl-2.3.4.so)
   by 0x9E6E3B: dlsym (in /lib/libdl-2.3.4.so)
   by 0x1B9106EE: open (vg_libpthread.c:2339)

LEAK SUMMARY:
   definitely lost: 0 bytes in 0 blocks.
   possibly lost:   0 bytes in 0 blocks.
   still reachable: 16 bytes in 1 blocks.
===============================================================

无论创建多少个线程，我都会得到相同的泄漏摘要。因为泄漏所在的文件是一个系统文件，而不是我自己的文件，我已经正确实现了一些东西。它可能是什么？

我在另一个Linux服务器上的valgrind中运行相同的文件，现在我得到了这个：

==12599== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 4 from 1)
==12599== malloc/free: in use at exit: 136 bytes in 1 blocks.
==12599== malloc/free: 6 allocs, 5 frees, 184 bytes allocated.
==12599== For counts of detected errors, rerun with: -v
==12599== searching for pointers to 1 not-freed blocks.
==12599== checked 10,580,680 bytes.
==12599==
==12599== 136 bytes in 1 blocks are possibly lost in loss record 1 of 1
==12599==    at 0x4905D27: calloc (vg_replace_malloc.c:279)
==12599==    by 0x358500D332: _dl_allocate_tls (in /lib64/ld-2.3.4.so)
==12599==    by 0x3585F066EE: pthread_create@@GLIBC_2.2.5 (in /lib64/tls/libpthr
ead-2.3.4.so)
==12599==    by 0x401222: main (test36.c:81)
==12599==
==12599== LEAK SUMMARY:
==12599==    definitely lost: 0 bytes in 0 blocks.
==12599==      possibly lost: 136 bytes in 1 blocks.
==12599==    still reachable: 0 bytes in 0 blocks.
==12599==         suppressed: 0 bytes in 0 blocks.

这是服务器的问题吗？仅供参考：行号test.c中的81是pthread_create调用。我的创建电话有问题吗？

Answer 1

我认为你没有什么可担心的。泄漏摘要说：

LEAK SUMMARY:
definitely lost: 0 bytes in 0 blocks.
possibly lost: 0 bytes in 0 blocks.
still reachable: 16 bytes in 1 blocks.

和'仍然可以访问'内存并没有明确丢失，并且它似乎在您识别的系统代码中，并且它不会随着线程数量的增加而增加，所有这些都加起来“无需担心”在我的书中。

除非内存量急剧增加，或者您可以确定代码可能泄漏内存的方式，否则请花时间处理其他问题而不是这个问题。

Answer 2

当我看到这个时，有些东西引起了我的注意：

    thread_return = pthread_create((th+thread_counter), NULL
                                   ,thread_func,(void*)&connfd);

它将connfd的地址传递给另一个线程。如何分配connfd？它不是局部变量，是吗？

Answer 3

这只是意味着在结束程序之前没有释放所有已分配的内存。释放所有的alloc指针，这个警告应该消失。

使用C中的多个分离线程进行内存泄漏

3 个答案: