.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved 
.TH "ENDGRENT" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\" endgrent 
.SH 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.
.SH NAME
endgrent, getgrent, setgrent \- group database entry functions
.SH SYNOPSIS
.LP
\fB#include <grp.h>
.br
.sp
void endgrent(void);
.br
struct group *getgrent(void);
.br
void setgrent(void); \fP
\fB
.br
\fP
.SH DESCRIPTION
.LP
The \fIgetgrent\fP() function shall return a pointer to a structure
containing the broken-out fields of an entry in the group
database. When first called, \fIgetgrent\fP() shall return a pointer
to a \fBgroup\fP structure containing the first entry in the
group database. Thereafter, it shall return a pointer to a \fBgroup\fP
structure containing the next group structure in the group
database, so successive calls may be used to search the entire database.
.LP
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.
.LP
The \fIsetgrent\fP() function shall rewind the group database to allow
repeated searches.
.LP
The \fIendgrent\fP() function may be called to close the group database
when processing is complete.
.LP
These functions need not be reentrant. A function that is not required
to be reentrant is not required to be thread-safe.
.SH RETURN VALUE
.LP
When first called, \fIgetgrent\fP() 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 \fIgetgrent\fP() function shall return a null pointer on
end-of-file or an error and \fIerrno\fP may be set to indicate the
error.
.LP
The return value may point to a static area which is overwritten by
a subsequent call to \fIgetgrgid\fP(), \fIgetgrnam\fP(), or
\fIgetgrent\fP().
.SH ERRORS
.LP
The \fIgetgrent\fP() function may fail if:
.TP 7
.B EINTR
A signal was caught during the operation.
.TP 7
.B EIO
An I/O error has occurred.
.TP 7
.B EMFILE
{OPEN_MAX} file descriptors are currently open in the calling process.
.TP 7
.B ENFILE
The maximum allowable number of files is currently open in the system.
.sp
.LP
\fIThe following sections are informative.\fP
.SH EXAMPLES
.LP
None.
.SH APPLICATION USAGE
.LP
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 \fIgetgrnam\fP() and \fIgetgrgid\fP()
whenever possible because it avoids these dependencies.
.SH RATIONALE
.LP
None.
.SH FUTURE DIRECTIONS
.LP
None.
.SH SEE ALSO
.LP
\fIgetgrgid\fP(), \fIgetgrnam\fP(), \fIgetlogin\fP(), \fIgetpwent\fP(),
the Base Definitions volume of
IEEE\ Std\ 1003.1-2001, \fI<grp.h>\fP
.SH 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 .