endpwent(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():
       _XOPEN_SOURCE >= 500
           || /* Glibc since 2.19: */ _DEFAULT_SOURCE
           || /* Glibc versions <= 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 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; 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(),  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

   This page is part of release 4.09 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/.

---

Free and Open Source Software