GETPWENT(3) Linux Programmer's Manual GETPWENT(3)NAME
getpwent, setpwent, endpwent - get password file entry
SYNOPSIS
#include <sys/types.h>
#include <pwd.h>
struct passwd *getpwent(void);
void setpwent(void);
void endpwent(void);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
getpwent(), setpwent(), endpwent():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 ||
_XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
DESCRIPTION
The getpwent() function returns a pointer to a structure containing the
broken-out fields of a record from the password database (e.g., the
local password file /etc/passwd, NIS, and LDAP). The first time getp‐
went() is called, it returns the first entry; thereafter, it returns
successive entries.
The setpwent() function rewinds to the beginning of the password data‐
base.
The endpwent() function is used to close the password database after
all processing has been performed.
The passwd structure is defined in <pwd.h> as follows:
struct passwd {
char *pw_name; /* username */
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 */
};
When shadow(5) passwords are enabled (which is default on many
GNU/Linux installations) the content of pw_passwd is usually not very
useful. In such a case most passwords are stored in a separate file.
The variable pw_shell may be empty, in which case the system will exe‐
cute the default shell (/bin/sh) for the user.
RETURN VALUE
The getpwent() function returns a pointer to a passwd structure, or
NULL if there are no more entries or an error occured. If an error
occurs, errno is set appropriately. If one wants to check errno after
the call, it should be set to zero before the call.
The return value may point to a static area, and may be overwritten by
subsequent calls to getpwent(), getpwnam(3), or getpwuid(3). (Do not
pass the returned pointer to free(3).)
ERRORS
EINTR A signal was caught.
EIO I/O error.
EMFILE The maximum number (OPEN_MAX) of files was open already in the
calling process.
ENFILE The maximum number of files was open already in the system.
ENOMEM Insufficient memory to allocate passwd structure.
ERANGE Insufficient buffer space supplied.
FILES
/etc/passwd
local password database file
CONFORMING TO
SVr4, 4.3BSD, POSIX.1-2001.
SEE ALSOfgetpwent(3), getpw(3), getpwent_r(3), getpwnam(3), getpwuid(3), putp‐
went(3), shadow(5), passwd(5)COLOPHON
This page is part of release 3.27 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
GNU 2010-09-20 GETPWENT(3)
