示例代码：查看进程中环境变量中所有的值。

#include <stdio.h>int main(){extern char** environ;for (char** pp = environ; *pp; pp++){printf("%s\n", *pp);}return 0;
}

输出结果：

SHELL=/bin/bash
WSL2_GUI_APPS_ENABLED=1
WSL_DISTRO_NAME=Ubuntu-22.04
NAME=pc
PWD=/home/zhangdapeng/code/helloc
LOGNAME=zhangdapeng
MOTD_SHOWN=update-motd
HOME=/home/zhangdapeng
LANG=C.UTF-8
WSL_INTEROP=/run/WSL/378_interop
...
WAYLAND_DISPLAY=wayland-0
LESSCLOSE=/usr/bin/lesspipe %s %s
TERM=xterm-256color
LESSOPEN=| /usr/bin/lesspipe %s
USER=zhangdapeng
DISPLAY=:0
SHLVL=1
XDG_RUNTIME_DIR=/run/user/1000/
...
HOSTTYPE=x86_64
PULSE_SERVER=unix:/mnt/wslg/PulseServer
_=./test
OLDPWD=/home/zhangdapeng/code