Manpages - getpwent.3

Table of Contents

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*():

      _XOPEN_SOURCE >= 500
          || /* Glibc since 2.19: */ _DEFAULT_SOURCE
          || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

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;      /* user information */
      char   *pw_dir;        /* home directory */
      char   *pw_shell;      /* shell program */
  };

For more information about the fields of this structure, see *passwd*(5).

RETURN VALUE

The *getpwent*() function returns a pointer to a passwd structure, or NULL if there are no more entries or an error occurred. If an error occurs, errno is set to indicate the error. 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; see *signal*(7).
EIO
I/O error.
EMFILE
The per-process limit on the number of open file descriptors has been reached.
ENFILE
The system-wide limit on the total number of open files has been reached.
ENOMEM
Insufficient memory to allocate passwd structure.
ERANGE
Insufficient buffer space supplied.

FILES

/etc/passwd
local password database file

ATTRIBUTES

For an explanation of the terms used in this section, see *attributes*(7).

Interface Attribute Value
*getpwent*() Thread safety MT-Unsafe race:pwent race:pwentbuf locale
*setpwent*(), *endpwent*() Thread safety MT-Unsafe race:pwent locale

In the above table, pwent in race:pwent signifies that if any of the functions *setpwent*(), *getpwent*(), or *endpwent*() are used in parallel in different threads of a program, then data races could occur.

CONFORMING TO

POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD. The pw_gecos field is not specified in POSIX, but is present on most implementations.

SEE ALSO

*fgetpwent*(3), *getpw*(3), *getpwent_r*(3), *getpwnam*(3), *getpwuid*(3), *putpwent*(3), *passwd*(5)

COLOPHON

This page is part of release 5.13 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

Author: dt

Created: 2022-02-20 Sun 15:50