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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 dif-
       fer (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 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  restric-
       tions  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() 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(),  getgr-
       nam(), 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. 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.  Applications should use getgrnam() and getgrgid() whenever possible because it avoids these dependen-
       cies.

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, Stan-
       dard  for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifica-
       tions 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 Stan-
       dard, 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)