getpwuid和getpwnam的用法

如果知道一个用户的用户ID或者登录名,可以通过getpwuid或getpwnam函数获得用户的登录信息.
函数原型为:
      

   

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

 
    struct
     passwd 
    *
    getpwnam(
    const
     
    char
     
    *
    name);
 
    struct
     passwd 
    *
    getpwuid(uid_t uid);

 The passwd structure 
    is
     defined 
    in
     
    <
    pwd.h
    >
     
    as
     follows:

 
    struct
     passwd {
 
    char
     
    *
    pw_name; 
    /*
     user name 
    */
    
 
    char
     
    *
    pw_passwd; 
    /*
     user password 
    */
    
 uid_t pw_uid; 
    /*
     user id 
    */
    
 gid_t pw_gid; 
    /*
     group id 
    */
    
 
    char
     
    *
    pw_gecos; 
    /*
     real name 
    */
    
 
    char
     
    *
    pw_dir; 
    /*
     home directory 
    */
    
 
    char
     
    *
    pw_shell; 
    /*
     shell program 
    */
    
 };
   

使用举例:

   

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


    int
     main()
{
 uid_t my_uid;
 my_uid 
    =
     
    500
    ;

 
    struct
     passwd 
    *
    my_info;

 my_info 
    =
     getpwuid( my_uid );
 
    //
    my_info = getpwnam( "fflg" );
    

    
 printf( 
    "
    my name = [%s]\n
    "
    , my_info
    ->
    pw_name );
 printf( 
    "
    my passwd = [%s]\n
    "
    , my_info
    ->
    pw_passwd );
 printf( 
    "
    my uid = [%d]\n
    "
    , my_info
    ->
    pw_uid );
 printf( 
    "
    my gid = [%d]\n
    "
    , my_info
    ->
    pw_gid );
 printf( 
    "
    my gecos = [%s]\n
    "
    , my_info
    ->
    pw_gecos );
 printf( 
    "
    my dir = [%s]\n
    "
    , my_info
    ->
    pw_dir );
 printf( 
    "
    my shell = [%s]\n
    "
    , my_info
    ->
    pw_shell );

 
    return
     
    0
    ;
}