pwd.h中的函数

看手册：

The <pwd.h> header shall provide a definition for struct passwd, which shall include at least the following members:

char    *pw_name   User's login name. 
uid_t    pw_uid    Numerical user ID. 
gid_t    pw_gid    Numerical group ID. 
char    *pw_dir    Initial working directory. 
char    *pw_shell  Program to use as shell. 

测试：

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include <pwd.h>
#include <sys/types.h>

int main(int argc, char *argv[])
{
    
    struct passwd *my_info;
    if(argc!=2)
    {
        printf("usage: %s username\n",argv[0]);
        exit(0);
    }
    my_info = getpwnam(argv[1]);
    if(my_info==NULL)
    {
        printf("could not find user '%s'\n",argv[1]);
        exit(1);
    }
    printf( "name = %s\n", my_info->pw_name );
    printf( "uid = %d\n", my_info->pw_uid );
    printf( "gid = %d\n", my_info->pw_gid );
    printf( "dir = %s\n", my_info->pw_dir );
    printf( "shell = %s\n", my_info->pw_shell );
    return 0;
}

 另外一个是getpwuid函数，使用起来是差不多的。