Linux 系统库函数coreleft 与sbrk简介

coreleft

 

函数名: coreleft

功 能: 返回未使用内存的大小

用 法: unsigned coreleft(void);

程序例:

#include <stdio.h>

#include <alloc.h>

int main(void)

{

printf("The difference between the highest allocated block and\n");

printf("the top of the heap is: %lu bytes\n", (unsigned long) coreleft());

return 0;

}

 

sbrk

 

函数名: sbrk

功 能: 增加程序可用数据段空间，增加大小由参数 incr决定 。

返回值：函数调用成功返回一指针，指向新的内存空间。函数调用失败则返回 -1,将errno设为ENOMEM。

用 法: char *sbrk(int incr);

程序例:

#include <stdio.h>

#include <alloc.h>

int main(void)

{

printf("Changing allocation with sbrk()\n");

printf("Before sbrk() call: %lu bytes free\n",

(unsigned long) coreleft());

sbrk(1000);

printf(" After sbrk() call: %lu bytes free\n",

(unsigned long) coreleft());

return 0;

}