Pthread導致的memory leak

今天在解決客戶的一個內存泄露的問題，客戶提供了source code，但從代碼語法，代碼結構上的檢查，都沒有發現什麼問題，編碼風格還算整潔，那爲什麼還有Memory Leak？

客戶代碼有一個特點，使用了多線程，而且用得還比較頻繁，而且初看代碼，也沒有問題，線和有創建pthread_create, 都會有退出pthread_exit，那問題在那裏，於是，就查看了下linux的api手冊，仔細研究了下linux 的thread.

##Linux如此說

A thread may either  be  joinable  or  detached.   If  a  thread  is  joinable,  then  another  thread  can  call
       pthread_join(3)  to  wait for the thread to terminate and fetch its exit status.  Only when a terminated joinable
       thread has been joined are the last of its resources released back to the system.  When a detached thread  termi‐
       nates, its resources are automatically released back to the system: it is not possible to join with the thread in
       order to obtain its exit status.  Making a thread detached is useful for some types of daemon threads whose  exit
       status  the  application  does  not need to care about.  By default, a new thread is created in a joinable