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 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 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

ATTRIBUTES
   Multithreading (see pthreads(7))
       The getpwent() function is not thread-safe.

       The setpwent() and endpwent() functions are thread-safe.

CONFORMING TO
       SVr4, 4.3BSD, POSIX.1-2001.  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
       This page is part of release 3.74 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 http://www.kernel.org/doc/man-pages/.



GNU                                         2013-06-21                                GETPWENT(3)