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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 (consult 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  contain-
       ing the broken-out fields of an entry in the group database. When first
       called, getgrent() shall return a pointer to a group structure contain-
       ing  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  caller 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() func-
       tion 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 getgrent().
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.  Applica-
       tions  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. Applications should use getgrnam() and get-
       grgid() 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, Copyright (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.opengroup.org/unix/online.html .

IEEE/The Open Group                  2003                         ENDGRENT(3P)