GETPWENT

Section: Linux Programmer's Manual (3)
Updated: 2010-09-20
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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 getpwent() is called, it returns the first entry; thereafter, it returns successive entries.

The setpwent() function rewinds to the beginning of the password database.

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 execute 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.

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/.

This document was created by man2html, using the manual pages.
Time: 19:49:21 GMT, April 27, 2011