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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;      /* user information */
               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.

       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  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 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).

       ┌────────────┬───────────────┬─────────────────────────────┐
       │InterfaceAttributeValue                       │
       ├────────────┼───────────────┼─────────────────────────────┤
       │getpwent()  │ Thread safety │ MT-Unsafe race:pwent        │
       │            │               │ race:pwentbuf locale        │
       ├────────────┼───────────────┼─────────────────────────────┤
       │setpwent(), │ Thread safety │ MT-Unsafe race:pwent locale │
       │endpwent()  │               │                             │
       └────────────┴───────────────┴─────────────────────────────┘
       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), shadow(5),
       passwd(5)

COLOPHON

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       project,  information  about  reporting  bugs, and the latest version of this page, can be
       found at http://www.kernel.org/doc/man-pages/.