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回复 27# lin5161678
不好意思,上一个有些修改struct..{ int *p}//我改成了int p[10]- [root@speedlinux ~]# gdb a.out
- GNU gdb (Ubuntu/Linaro 7.4-2012.04-0ubuntu2) 7.4-2012.04
- Copyright (C) 2012 Free Software Foundation, Inc.
- License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
- This is free software: you are free to change and redistribute it.
- There is NO WARRANTY, to the extent permitted by law. Type "show copying"
- and "show warranty" for details.
- This GDB was configured as "i686-linux-gnu".
- For bug reporting instructions, please see:
- <http://bugs.launchpad.net/gdb-linaro/>...
- Reading symbols from /root/a.out...done.
- (gdb) list
- 4
- 5 using namespace std;
- 6
- 7 struct STEST {
- 8 int i;
- 9 int *p;
- 10 };
- 11
- 12 int main(void)
- 13 {
- (gdb)
- 14 struct STEST x;
- 15 int *p = &x.i;
- 16 p[0] = 4;
- 17 p[1] = 3;
- 18
- 19 string s1="test";
- 20 char msgBuffer[256]={0};
- 21 if(!s1.empty())
- 22 sprintf(msgBuffer, "s1:%s\n",s1.c_str());
- 23 x.p[0]=5;
- (gdb)
- 24 printf("msgBuffer%s,%d\n", msgBuffer, x.i,*x.p);
- 25 return 0;
- 26 }
- (gdb)
- Line number 27 out of range; test.c has 26 lines.
- (gdb) break 15
- Breakpoint 1 at 0x8048801: file test.c, line 15.
- (gdb) break 16
- Breakpoint 2 at 0x8048809: file test.c, line 16.
- (gdb) break 17
- Breakpoint 3 at 0x8048813: file test.c, line 17.
- (gdb) break 19
- Breakpoint 4 at 0x8048820: file test.c, line 19.
- (gdb) break 20
- Breakpoint 5 at 0x8048854: file test.c, line 20.
- (gdb) break 21
- Breakpoint 6 at 0x8048868: file test.c, line 21.
- (gdb) break 22
- Breakpoint 7 at 0x804887b: file test.c, line 22.
- (gdb) break 23
- Breakpoint 8 at 0x804889f: file test.c, line 23.
- (gdb) break 24
- Breakpoint 9 at 0x80488a9: file test.c, line 24.
- (gdb) run
- Starting program: /root/a.out
- Breakpoint 1, main () at test.c:15
- 15 int *p = &x.i;
- (gdb) p *p
- $1 = -1208203904
- (gdb) p x.i
- $2 = -1210944584
- (gdb) p &x.i
- $3 = (int *) 0xbffff398
- (gdb) p *x.p
- $4 = -1210974208
- (gdb) n
- Breakpoint 2, main () at test.c:16
- 16 p[0] = 4;
- (gdb) p p[0]
- $5 = -1210944584
- (gdb) p x.i
- $6 = -1210944584
- (gdb) n
- Breakpoint 3, main () at test.c:17
- 17 p[1] = 3;
- (gdb) p p[0]
- $7 = 4
- (gdb) p x.i
- $8 = 4
- (gdb) p p[1]
- $9 = -1209229312
- (gdb) p *x.p
- $10 = -1210974208
- (gdb) n
- Breakpoint 4, main () at test.c:19
- 19 string s1="test";
- (gdb) p *x.p
- Cannot access memory at address 0x3
- (gdb) p p[1]
- $11 = 3
- (gdb) p x.p[0]
- Cannot access memory at address 0x3
- (gdb) p x.p[1]
- Cannot access memory at address 0x7
- (gdb) n
- Breakpoint 5, main () at test.c:20
- 20 char msgBuffer[256]={0};
- (gdb) p msgBuffer[0]
- $12 = -42 '\326'
- (gdb) p msgBuffer[1]
- $13 = 10 '\n'
- (gdb) p msgBuffer[2]
- $14 = -8 '\370'
- (gdb) p msgBuffer[0]@256
- $15 = "\326\n\370\267\377\377\377\377,.\374\267\370K\374\267\000\000\000\000\334\363\377\277\364\357\377\267\030\371\377\267\001\000\000\000\000\000\000\000\213\302\376\267\320\372\377\267C0辗\001\000\000\000\001\000\000\000\000\000\000\000i,\365\267\244t\374\267\020u\374\267\200E\374\267\364_\354\267\000\000\000\000\001\000\000\000h\364\377\277\253\061辗\344c旆竤曳\000\000\000\000C0辗\001\000\000\000\226\061辗\364_\354\267%2辗\220\206\004\bP\240\004\bD\240\004\b\344c旆怽206\004\b\366\061辗\364\237\004\bn\211\004\b\220\206\004\bP\240\004\bD\240\004\b%2辗03\364\267\270\210\374\267\210\364\377\277\212\211\004\b\001\000\000\000\377\377\000\000\001\000\000\000\r\206\004\b\344c旆竆210\374\267\001\000\000\000\342\211\004\b\001\000\000\000T\365\377\277\\\365\377\277%2辗p\322\376\267\000\000\000\000\231\211\004\b"
- (gdb) n
- Breakpoint 6, main () at test.c:21
- 21 if(!s1.empty())
- (gdb) p msgBuffer[0]@256
- $16 = '\000' <repeats 255 times>
- (gdb) n
- Breakpoint 7, main () at test.c:22
- 22 sprintf(msgBuffer, "s1:%s\n",s1.c_str());
- (gdb) p msgBuffer[0]@256
- $17 = '\000' <repeats 255 times>
- (gdb) n
- Breakpoint 8, main () at test.c:23
- 23 x.p[0]=5;
- (gdb) p x.p[0]
- Cannot access memory at address 0x3
- (gdb) n
- Program received signal SIGSEGV, Segmentation fault.
- 0x080488a3 in main () at test.c:23
- 23 x.p[0]=5;
- (gdb) p x.p[0]
- Cannot access memory at address 0x3
- (gdb) p x.p[1]
- Cannot access memory at address 0x7
- (gdb) p p[1]
- $18 = 3
- (gdb) p *x.p
- Cannot access memory at address 0x3
- (gdb) p msgBuffer, x.i,*x.p
- Cannot access memory at address 0x3
- (gdb) p msgBuffer
- $19 = "s1:test\n", '\000' <repeats 247 times>
- (gdb) p x.i
- $20 = 4
- (gdb) p *x.p
- Cannot access memory at address 0x3
- (gdb) quit
- A debugging session is active.
- Inferior 1 [process 3458] will be killed.
- Quit anyway? (y or n) y
- [root@speedlinux ~]#
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楼主: lsupper
发表于 2012-11-06 11:44
