怎么查看动态分配内存空间的大小(GNU linux下C语言版)

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RT，经过几番纠结，终于找到了GNU like UNIX平台下得到malloc后的大小的方法，

microsoft有_msize可完成类似功能，现将测试代码甩上来，以咨参考

/********************************************************************

* Function: Test malloc and realloc,get malloc size

* Author : Samson

* Date : 11/23/2011

* Test platform:

* GNU Linux version 2.6.29.4

* gcc version 4.4.0 20090506 (Red Hat 4.4.0-4) (GCC)

* Online citations: http://fuse4bsd.creo.hu/localcgi/man-cgi.cgi?malloc+3
* *****************************************************************/

#include <stdio.h>

#include <stdlib.h>

#include <malloc.h>

int

main()

{

char *strP, *tem2P;

int ntem;

strP = malloc(20);

ntem = malloc_usable_size(strP);

printf("first malloc_usable_size is %d\n", ntem);

tem2P = strP;

if(NULL != realloc(strP, 100))

{

ntem = malloc_usable_size(strP);

printf("realloc malloc_usable_size is %d\n", ntem);

}

free(tem2P);

exit(0);

}

run result:

[root@UFO]# ./a.out

first malloc_usable_size is 20

realloc malloc_usable_size is 100