linux下的四个简单函数介绍 getpid getppid getuid getgid

秒速五厘米 2022-04-16 03:53 309阅读 0赞

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直接看程序：

#include <stdio.h>int main(){ printf("pid:%d, ppid:%d, uid:%d, gid:%d\n", getpid(), getppid(), getuid(), getgid()); return 0;}

结果为：

\[taoge@localhost learn\_c\]$ echo $$  
2774  
\[taoge@localhost learn\_c\]$ id  
uid=501(taoge) gid=502(taoge) groups=502(taoge),501(embed)  
\[taoge@localhost learn\_c\]$ ./a.out   
pid:2898, ppid:2774, uid:501, gid:502

\[taoge@localhost learn\_c\]$ su root  
Password:   
\[root@localhost learn\_c\]\# echo &&  
>   
> ^C  
\[root@localhost learn\_c\]\# id  
uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),10(wheel)  
\[root@localhost learn\_c\]\# ./a.out   
pid:2922, ppid:2905, uid:0, gid:0

\[root@localhost learn\_c\]\# su taoge  
\[taoge@localhost learn\_c\]$ echo $$  
2928  
\[taoge@localhost learn\_c\]$ id  
uid=501(taoge) gid=502(taoge) groups=502(taoge),501(embed)  
\[taoge@localhost learn\_c\]$ ./a.out   
pid:2946, ppid:2928, uid:501, gid:502  
\[taoge@localhost learn\_c\]$

ok,  无需多说。

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