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Creation-Date: 2012-12-25T21:45:29+08:00

====== gdb pointer ======
Created Tuesday 25 December 2012
[geekard@geekard elf]$ **cat array.c**
#include <stdio.h>
#include <stdlib.h>

int main(void)
{
   int ia[3] = {1,2,3};
   char *cpa[3] = {"Tom", "John", NULL};
   char *cpa2[] = {"Tom", "John", NULL};
   char **cpa3 = {"Tom", "John", NULL};
}
[geekard@geekard elf]$ **gcc -g array.c -o array**
array.c: In function ‘main’:
array.c:9:4: warning: initialization from incompatible pointer type [enabled by default]
array.c:9:4: warning: (near initialization for ‘cpa3’) [enabled by default]
array.c:9:4: warning: excess elements in scalar initializer [enabled by default]
array.c:9:4: warning: (near initialization for ‘cpa3’) [enabled by default]
array.c:9:4: warning: excess elements in scalar initializer [enabled by default]
array.c:9:4: warning: (near initialization for ‘cpa3’) [enabled by default]
[geekard@geekard elf]$ **gdb array**
GNU gdb (GDB) 7.5.1
。。。。。
**(gdb) list main**
1       #include <stdio.h>
2       #include <stdlib.h>
3
4       int main(void)
5       {
6          int ia[3] = {1,2,3};  
7          char *cpa[3] = {"Tom", "John", NULL};
8          char *cpa2[] = {"Tom", "John", NULL};  //ia, cpa, cpa2为数组首地址的引用名称，而非变量，不占用
9          char **cpa3 = {"Tom", "John", NULL};
10      }
**(gdb) b 10**
Breakpoint 1 at 0x8048418: file array.c, line 10.
**(gdb) r**
Starting program: /home/geekard/Code/elf/array 
warning: Could not load shared library symbols for linux-gate.so.1.
Do you need "set solib-search-path" or "set sysroot"?

Breakpoint 1, main () at array.c:10
10      }
**(gdb) disassemble main**
Dump of assembler code for function main:
   0x080483cc <+0>:     push   %ebp
   0x080483cd <+1>:     mov    %esp,%ebp
   0x080483cf <+3>:     sub    $0x30,%esp
   0x080483d2 <+6>:     movl   $0x1,-0x10(%ebp)
   0x080483d9 <+13>:    movl   $0x2,-0xc(%ebp)
   0x080483e0 <+20>:    movl   $0x3,-0x8(%ebp)
   0x080483e7 <+27>:    movl   $0x80484b0,-0x1c(%ebp)
   0x080483ee <+34>:    movl   $0x80484b4,-0x18(%ebp)
   0x080483f5 <+41>:    movl   $0x0,-0x14(%ebp)
   0x080483fc <+48>:    movl   $0x80484b0,-0x28(%ebp)
   0x08048403 <+55>:    movl   $0x80484b4,-0x24(%ebp)
   0x0804840a <+62>:    movl   $0x0,-0x20(%ebp)
   0x08048411 <+69>:    movl   $0x80484b0,-0x4(%ebp)
=> 0x08048418 <+76>:    leave  
   0x08048419 <+77>:    ret    
End of assembler dump.
**(gdb) bt**
#0  main () at array.c:10
**(gdb) info f 0**
Stack frame at 0xbffff980:
 eip = 0x8048418 in main (array.c:10); saved eip 0xb7e28605
 source language c.
 Arglist at 0xbffff978, args: 
 Locals at 0xbffff978, Previous frame's sp is 0xbffff980
 Saved registers:
  ebp at 0xbffff978, eip at 0xbffff97c
**(gdb) info locals** 
ia = {1, 2, 3}
cpa = {0x80484b0 "Tom", 0x80484b4 "John", 0x0}
cpa2 = {0x80484b0 "Tom", 0x80484b4 "John", 0x0}
__cpa3 = 0x80484b0__
//可见ia, cpa, cpa2为数组名称，而cpa3为一指针变量，其值为0x80484b0。