gdb，break vs tbreak和watchpoint

Question

谁能告诉我关于watchpoint的break和tbreak有什么区别？

A具有一个简单的测试代码：

#include <stdlib.h> 
#include <stdio.h> 

int main(int argc, char **argv) { 
    int toto; 
    toto = 1; 
    toto = 2; 
    toto = 3; 
    return (EXIT_SUCCESS); 
} 

当我使用上main（）中，然后观察断裂，TOTO似乎切换为0〜2：

(gdb) break main 
Breakpoint 1 at 0x804839a: file pp.c, line 6. 
(gdb) r 
Starting program: /mnt/mega20/SRC/C/gdb/pp 

Breakpoint 1, main (argc=1, argv=0xbffff4f4) at pp.c:6 
6   toto = 1; 
(gdb) watch toto 
Hardware watchpoint 2: toto 
(gdb) c 
Continuing. 
Hardware watchpoint 2: toto 

Old value = 0 
New value = 2 
main (argc=1, argv=0xbffff4f4) at pp.c:8 
8   toto = 3; 
(gdb) 

但是当我使用手表似乎工作：

(gdb) tbreak main 
Temporary breakpoint 1 at 0x804839a: file pp.c, line 6. 
(gdb) r 
Starting program: /mnt/mega20/SRC/C/gdb/pp 

Temporary breakpoint 1, main (argc=1, argv=0xbffff4f4) at pp.c:6 
6   toto = 1; 
(gdb) watch toto 
Hardware watchpoint 2: toto 
(gdb) c 
Continuing. 
Hardware watchpoint 2: toto 

Old value = 0 
New value = 1 
main (argc=1, argv=0xbffff4f4) at pp.c:7 
7   toto = 2; 
(gdb) c 
Continuing. 
Hardware watchpoint 2: toto 

Old value = 1 
New value = 2 
main (argc=1, argv=0xbffff4f4) at pp.c:8 
8   toto = 3; 
(gdb) 

与启动命令相同的结果，它的工作原理。

Answer 1

我建议你阅读本：

Breakpoints and Watchpoints