# 设置条件断点 ## 例子 #include <stdio.h> int main(void) { int i = 0; int sum = 0; for (i = 1; i <= 200; i++) { sum += i; } printf("%d\n", sum); return 0; } ## 技巧 gdb可以设置条件断点，也就是只有在条件满足时，断点才会被触发，命令是“`break … if cond`”。以上面程序为例： (gdb) start Temporary breakpoint 1 at 0x4004cc: file a.c, line 5. Starting program: /data2/home/nanxiao/a Temporary breakpoint 1, main () at a.c:5 5 int i = 0; (gdb) b 10 if i==101 Breakpoint 2 at 0x4004e3: file a.c, line 10. (gdb) r Starting program: /data2/home/nanxiao/a Breakpoint 2, main () at a.c:10 10 sum += i; (gdb) p sum $1 = 5050 可以看到设定断点只在`i`的值为`101`时触发，此时打印`sum`的值为`5050`。 详情参见[gdb手册](https://sourceware.org/gdb/onlinedocs/gdb/Set-Breaks.html) ## 贡献者 nanxiao