# 利用Thread Sanitizer工具檢查數據競爭的問題 ## 例子 #include <pthread.h> int Global; void *Thread1(void *x) { Global = 42; return x; } int main(void) { pthread_t t; pthread_create(&t, NULL, Thread1, NULL); Global = 43; pthread_join(t, NULL); return Global; } ## 技巧 gcc從`4.8`版本起，集成了`Address Sanitizer`工具，可以用來檢查數據競爭的問題（編譯時指定“`-fsanitize=thread -fPIE -pie`”）。以上面程序為例： gcc -fsanitize=thread -fPIE -pie -g -o a a.c -lpthread 執行`a`程序： [root@localhost nan]# ./a ================== WARNING: ThreadSanitizer: data race (pid=14545) Write of size 4 at 0x7f055b4802b0 by thread T1: #0 Thread1 /home/nan/a.c:4 (a+0x000000000a87) Previous write of size 4 at 0x7f055b4802b0 by main thread: #0 main /home/nan/a.c:10 (a+0x000000000ae8) Location is global 'Global' of size 4 at 0x7f055b4802b0 (a+0x0000002012b0) Thread T1 (tid=14547, running) created by main thread at: #0 pthread_create /opt/gcc-4.9.2/src/gcc-4.9.2/libsanitizer/tsan/tsan_interceptors.cc:877 (libtsan.so.0+0x00000004aa83) #1 main /home/nan/a.c:9 (a+0x000000000ad9) SUMMARY: ThreadSanitizer: data race /home/nan/a.c:4 Thread1 ================== ThreadSanitizer: reported 1 warnings 可以看到，執行程序時檢測出了對`Global`變量的競爭訪問。 詳情參見[gcc手冊](https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Debugging-Options.html#index-fsanitize_003dthread-595) ## 貢獻者 nanxiao