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



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


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 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 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 application shall not modify the structure to which the return
       value points, nor any storage areas pointed to by pointers within the
       structure. The returned pointer, and pointers within the structure,
       might be invalidated or the structure or the storage areas might be
       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 All file descriptors available to the process are currently
              open.

       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 dependencies.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       endpwent(), getgrgid(), getgrnam(), getlogin()

       The Base Definitions volume of POSIX.1-2008, <grp.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open Group.  (This is
       POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2013                          ENDGRENT(3)
