system()函数似乎返回了我从它引起的进程中获得的退出代码的128倍.

从手册页：

RETURN VALUE
The value returned is -1 on error (e.g., fork(2)
failed), and the return status of the command other‐
wise.

这就是我所拥有的.

$ls tinker.c
tinker.c
$echo $?
0
$ls notexisting
ls: cannot access notexisting: No such file or directory
$echo $?
2
$cat tinker.c
#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    printf("%d\n", system("ls tinker.c"));
    printf("%d\n", system("ls notexisting"));
    return 0;
}
$gcc tinker.c -o tinker
$./tinker 
tinker.c
0
ls: cannot access notexisting: No such file or directory
512

第一个调用表明我没有收到故障,但返回代码看起来与我从手册页中读取的内容完全不同.我做错了什么？

解决方法:

从POSIX system(3)：

If command is not a null pointer, system() shall return the termination status of the command language interpreter in the format specified by waitpid().

要获取返回代码,您需要使用WEXITSTATUS宏.