NAME

getpwent, getpwuid, getpwnam, setpwent, endpwent, fgetpwent − get password file entry

SYNOPSIS

#include <pwd.h>

struct passwd ∗getpwent ( )

struct passwd ∗getpwuid (uid)
int uid;

struct passwd ∗getpwnam (name)
char ∗name;

void setpwent ( )

void endpwent ( )

struct passwd ∗fgetpwent (f)
FILE ∗f;

DESCRIPTION

getpwent, getpwuid and getpwnam each returns a pointer to an object with the following structure containing the broken-out fields of a line in the /etc/passwd file.  Each line in the file contains a “passwd” structure, declared in the <pwd.h> header file:

struct passwd {
char∗pw_name;
char∗pw_passwd;
intpw_uid;
intpw_gid;
char∗pw_age;
char∗pw_comment;
char∗pw_gecos;
char∗pw_dir;
char∗pw_shell;
};

This structure is declared in <pwd.h> so it is not necessary to redeclare it. 

The fields have meanings described in passwd(4).

getpwent when first called returns a pointer to the first passwd structure in the file; thereafter, it returns a pointer to the next passwd structure in the file; so successive calls can be used to search the entire file.  getpwuid searches from the beginning of the file until a numerical user id matching uid is found and returns a pointer to the particular structure in which it was found.  getpwnam searches from the beginning of the file until a login name matching name is found, and returns a pointer to the particular structure in which it was found.  If an end-of-file or an error is encountered on reading, these functions return a NULL pointer. 

A call to setpwent has the effect of rewinding the password file to allow repeated searches.  endpwent may be called to close the password file when processing is complete. 

fgetpwent returns a pointer to the next passwd structure in the stream f, which matches the format of /etc/passwd.

FILES

/etc/passwd

SEE ALSO

getlogin(3C), getgrent(3C), passwd(4)

DIAGNOSTICS

A NULL pointer is returned on EOF or error. 

WARNING

These routines use <stdio.h>, causing a greater than expected increase in the size of programs not otherwise using standard I/O. 

CAVEAT

All information is contained in a static area, so it must be copied if it is to be saved. 

September 29, 2021