valgrind使用記錄

valgrind介紹參考文章：

https://blog.csdn.net/sduliulun/article/details/7732906

使用valgrind工具進行記憶體檢測，執行如下指令：

valgrind --tool=memcheck --leak-check=full --show-leak-kinds=all  -v ./tlx_process

遇到的記憶體洩漏問題以及解決方案：

1.Linux下正确使用getifaddrs()函數避免記憶體洩露

https://blog.csdn.net/tao_627/article/details/45062781

2.遇到多個可使目前函數退出的情況，在退出前，要釋放已申請的資源，可以考慮使用goto語句來整理代碼結構

此狀況時調用cJSON庫時，對解析出來的資料，進行多個函數傳參的情況下發生

https://blog.csdn.net/shimazhuge/article/details/8448773

https://www.cnblogs.com/heartchord/p/4795337.html

3.對于建立線程，定時器的記憶體洩漏，可以根據是否頻繁的操作而選擇是否進行修改

https://www.xuebuyuan.com/1568906.html

線程頻繁建立，未銷毀，導緻洩漏，需要主動銷毀不使用的線程

https://www.cnblogs.com/lidabo/archive/2012/08/15/2640204.html

https://blog.csdn.net/inuyashaw/article/details/53465294

https://www.cnblogs.com/fushou/p/7269564.html

4.valgrind提示有洩漏，但是實際情況卻沒有的狀況

==27558== 88 bytes in 1 blocks are still reachable in loss record 4 of 15

==27558==    at 0x4C29BC3: malloc (vg_replace_malloc.c:299)

==27558==    by 0x5357F8A: [email protected]@GLIBC_2.3.3 (in /usr/lib64/librt-2.17.so)

==27558==    by 0x4077D6: set_timer_up (client_timer.c:28)

==27558==    by 0x40A384: pthread_httpd_server (httpd.c:563)

==27558==    by 0x513FE24: start_thread (in /usr/lib64/libpthread-2.17.so)

==27558==    by 0x565ABAC: clone (in /usr/lib64/libc-2.17.so)

==27558==

經測試，timer_create 沒有記憶體洩漏，但是打開太多，會造成線程建立失敗，達到可建立句柄的最大值，隻在普通使用者下會有此狀況，是以，建立定時器後，要記得關閉

參考：https://www.ibm.com/developerworks/cn/linux/l-cn-timers/

https://blog.csdn.net/leo9150285/article/details/8271910

==27558== 116 bytes in 1 blocks are definitely lost in loss record 5 of 15

==27558==    at 0x4C29BC3: malloc (vg_replace_malloc.c:299)

==27558==    by 0x55E6C90: __libc_alloc_buffer_allocate (in /usr/lib64/libc-2.17.so)

==27558==    by 0x566D11E: __resolv_conf_allocate (in /usr/lib64/libc-2.17.so)

==27558==    by 0x566B0F1: __resolv_conf_load (in /usr/lib64/libc-2.17.so)

==27558==    by 0x566C9D7: __resolv_conf_get_current (in /usr/lib64/libc-2.17.so)

==27558==    by 0x566B3E1: __res_vinit (in /usr/lib64/libc-2.17.so)

==27558==    by 0x566C4FA: maybe_init (in /usr/lib64/libc-2.17.so)

==27558==    by 0x566C66D: __resolv_context_get (in /usr/lib64/libc-2.17.so)

==27558==    by 0x56753B9: gethostbyname (in /usr/lib64/libc-2.17.so)

==27558==    by 0x407FA8: http_tcpclient_create (http.c:22)

==27558==    by 0x40850A: http_post (http.c:165)

==27558==    by 0x40E8BD: get_http_heart (init_tlx_process.c:1349)

經測試，gethostbyname 沒有記憶體洩漏

參考：http://www.cnblogs.com/LubinLew/p/Linux-gethostbyname.html