操作系统学习笔记(18)--bss段设置

 

bss段需要填充为0

 

#include "stdio.h"extern char __bss_start, end;int main() {printf("bss start %x /n", &__bss_start);printf("bss end %x /n", &end);printf("bss start %x /n", __bss_start);printf("bss end %x /n", end);char *p=&__bss_start;int len =&end - &__bss_start;printf("len %d /n", len);int i = 0;for(i=0; i< len; i++) {printf("char %d", *p++);}}

 

 

[root@localhost testc]#gcc bbs.c

[root@localhost testc]# ./a.out
bss start 8049704
bss end  804970c
bss start 0
bss end  0
len 8
char 0char 0char 0char 0char 0char 0char 0char 0

 

下面是别人的解释参考一下：__bss_start isn't a pointer, nor does it hold anything. It's just a number generated by the linker that states where the bss starts. i.e. __bss_start does not occupy any memory space, it is a label. You could just as easily declare it as a short or a char.