ENDGRENT(3P)                                        POSIX Programmer's Manual                                       ENDGRENT(3P)



PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (con-
       sult the corresponding Linux manual page for details of Linux behavior), or the  interface  may  not  be  implemented  on
       Linux.

NAME
       endgrent, getgrent, setgrent - group database entry functions

SYNOPSIS
       #include <grp.h>

       void endgrent(void);
       struct group *getgrent(void);
       void setgrent(void);


DESCRIPTION
       The  getgrent()  function shall return a pointer to a structure containing the broken-out fields of an entry in the group
       database. When first called, getgrent() shall return a pointer to a group structure containing the  first  entry  in  the
       group  database.  Thereafter,  it  shall return a pointer to a group structure containing the next group structure in the
       group database, so successive calls may be used to search the entire database.

       An implementation that provides extended security controls may  impose  further  implementation-defined  restrictions  on
       accessing  the  group  database.  In  particular,  the system may deny the existence of some or all of the group database
       entries associated with groups other than those groups associated with the caller and may omit users other than the call-
       er from the list of members of groups in database entries that are returned.

       The setgrent() function shall rewind the group database to allow repeated searches.

       The endgrent() function may be called to close the group database when processing is complete.

       These functions need not be reentrant. A function that is not required to be reentrant is not required to be thread-safe.

RETURN VALUE
       When  first called, getgrent() shall return a pointer to the first group structure in the group database. Upon subsequent
       calls it shall return the next group structure in the group database.   The  getgrent()  function  shall  return  a  null
       pointer on end-of-file or an error and errno may be set to indicate the error.

       The  return value may point to a static area which is overwritten by a subsequent call to getgrgid(), getgrnam(), or get-
       grent().

ERRORS
       The getgrent() function may fail if:

       EINTR  A signal was caught during the operation.

       EIO    An I/O error has occurred.

       EMFILE {OPEN_MAX} file descriptors are currently open in the calling process.

       ENFILE The maximum allowable number of files is currently open in the system.


       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       These functions are provided due to their historical usage. Applications should avoid dependencies on fields in the group
       database,  whether  the  database is a single file, or where in the file system name space the database resides. Applica-
       tions should use getgrnam() and getgrgid() whenever possible because it avoids these dependencies.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       getgrgid(), getgrnam(), getlogin(), getpwent(), the Base Definitions volume of IEEE Std 1003.1-2001, <grp.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003  Edition,  Standard  for
       Information  Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copy-
       right (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any
       discrepancy  between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group
       Standard  is  the  referee   document.   The   original   Standard   can   be   obtained   online   at   http://www.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                  ENDGRENT(3P)