c - 缺少新的环境变量

Question

我在我的程序中设置了一个新的环境变量，但我无法从 shell 中找到它:

int main()
{
    if(!setenv("TEST","22222",0)) perror("");
    sleep(1000);
    return 0;
}

我试试

$ a.out &
[3] 605
$ Success

$ cat /proc/605/environ|grep 2222
$ ps e 605|grep 2222
$

有什么想法吗？非常感谢。

Answer 1

如 man 5 proc 中所述(注意加粗的段落):

/proc/[pid]/environ

This file contains the initial environment that was setwhen the currently executing program was started viaexecve(2). The entries are separated by null bytes('\0'), and there may be a null byte at the end. Thus,to print out the environment of process 1, you would do:

$ cat /proc/1/environ | tr '\000' '\n'

If, after an execve(2), the process modifies itsenvironment (e.g., by calling functions such asputenv(3) or modifying the environ(7) variabledirectly), this file will not reflect those changes.