NAME

       getpwent, setpwent, endpwent - get password file entry

LIBRARY

       Standard C library (libc, -lc)

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 >= 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 */
           };

       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 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.

VERSIONS

       The pw_gecos field is not specified in POSIX, but is present on most implementations.

STANDARDS

       POSIX.1-2008.

HISTORY

       POSIX.1-2001, SVr4, 4.3BSD.

SEE ALSO

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