GETPWENT(3) Linux Programmer's Manual GETPWENT(3)

NAME
       getpwent, setpwent, endpwent - get password file entry

SYNOPSIS
       #include 
       #include 

       struct passwd *getpwent(void);

       void setpwent(void);

       void endpwent(void);

   Feature Test Macro Requirements for glibc (see featuretestmacros(7)):

       getpwent(), setpwent(), endpwent():
           BSDSOURCE || SVIDSOURCE || XOPENSOURCE >= 500 ||
           XOPENSOURCE && XOPENSOURCEEXTENDED

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  getp‐
       went()  is  called,  it returns the first entry; thereafter, it returns
       successive entries.

       The setpwent() function rewinds to the beginning of the password  data‐
       base.

       The  endpwent()  function  is used to close the password database after
       all processing has been performed.

       The passwd structure is defined in  as follows:

           struct passwd {
               char   *pwname;       /* username */
               char   *pwpasswd;     /* user password */
               uidt   pwuid;        /* user ID */
               gidt   pwgid;        /* group ID */
               char   *pwgecos;      /* user information */
               char   *pwdir;        /* home directory */
               char   *pwshell;      /* 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 occurs.  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 (OPENMAX) 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.

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

SEE ALSO
       fgetpwent(3), getpw(3), getpwentr(3), getpwnam(3), getpwuid(3),  putp‐
       went(3), passwd(5)

COLOPHON
       This  page  is  part of release 3.53 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.



GNU                               2013-06-21                       GETPWENT(3)