打印程序进程空间信息

a.c:
#include <stdio.h>
int func(int a, int b)
{
        int c = a * b;
        printf("c is %d\n", c);
}

int main(void)
{
        func(1, 2);
        return 0;
}


b.c:
#include <stdio.h>

int func1(int a)
{
        return 2 * a;
}

int func2(int a)
{
        int c = 0;
        c = 2 * func1(a);
        return c;
}

int func3(int a)
{
        int c = 0;
        c = 2 * func2(a);
        return c;
}

int main(void)
{
        printf("%d\n", func3(10));
        return 0;
}

技巧

使用gdb调试多个进程时，可以使用“maint info program-spaces”打印当前所有被调试的进程信息。以上面程序为例：

[root@localhost nan]# gdb a
GNU gdb (GDB) 7.8.1
......
Reading symbols from a...done.
(gdb) start
Temporary breakpoint 1 at 0x4004f9: file a.c, line 10.
Starting program: /home/nan/a 

Temporary breakpoint 1, main () at a.c:10
10              func(1, 2);
(gdb) add-inferior -exec b
Added inferior 2
Reading symbols from b...done.
(gdb) i inferiors b
Args must be numbers or '$' variables.
(gdb) i inferiors
  Num  Description       Executable        
  2    <null>            /home/nan/b       
* 1    process 15753     /home/nan/a       
(gdb) inferior 2
[Switching to inferior 2 [<null>] (/home/nan/b)]
(gdb) start
Temporary breakpoint 2 at 0x4004f9: main. (2 locations)
Starting program: /home/nan/b 

Temporary breakpoint 2, main () at b.c:24
24              printf("%d\n", func3(10));
(gdb) i inferiors
  Num  Description       Executable        
* 2    process 15902     /home/nan/b       
  1    process 15753     /home/nan/a       
(gdb) clone-inferior -copies 2
Added inferior 3.
Added inferior 4.
(gdb) i inferiors
  Num  Description       Executable        
  4    <null>            /home/nan/b       
  3    <null>            /home/nan/b       
* 2    process 15902     /home/nan/b       
  1    process 15753     /home/nan/a       
(gdb) maint info program-spaces
  Id   Executable        
  4    /home/nan/b       
        Bound inferiors: ID 4 (process 0)
  3    /home/nan/b       
        Bound inferiors: ID 3 (process 0)
* 2    /home/nan/b       
        Bound inferiors: ID 2 (process 15902)
  1    /home/nan/a       
        Bound inferiors: ID 1 (process 15753)

可以看到执行“maint info program-spaces”命令后，打印出当前有4个program-spaces（编号从1到4）。另外还有每个program-spaces对应的程序，inferior编号及进程号。

参见 gdb手册.