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.TH ENDGRENT "3P" 2013 "IEEE/The Open Group" "POSIX Programmer's Manual"

.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

\(em group database entry functions

.SH SYNOPSIS

.LP

.nf

#include <grp.h>

.P

void endgrent(void);

struct group *getgrent(void);

void setgrent(void);

.fi

.SH DESCRIPTION

The

\fIgetgrent\fR()

function shall return a pointer to a structure containing the broken-out

fields of an entry in the group database. When first called,

\fIgetgrent\fR()

shall return a pointer to a

.BR group

structure containing the first entry in the group database. Thereafter,

it shall return a pointer to a

.BR group

structure containing the next group structure in the group database, so

successive calls may be used to search the entire database.

.P

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.

.P

The

\fIsetgrent\fR()

function shall rewind the group database to allow repeated searches.

.P

The

\fIendgrent\fR()

function may be called to close the group database when processing is

complete.

.P

These functions need not be thread-safe.

.SH "RETURN VALUE"

When first called,

\fIgetgrent\fR()

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\fR()

function shall return a null pointer on end-of-file or an error and

.IR errno

may be set to indicate the error.

.P

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

\fIgetgrgid\fR(),

\fIgetgrnam\fR(),

or

\fIgetgrent\fR().

.SH ERRORS

The

\fIgetgrent\fR()

function may fail if:

.TP

.BR EINTR

A signal was caught during the operation.

.TP

.BR EIO

An I/O error has occurred.

.TP

.BR EMFILE

All file descriptors available to the process are currently open.

.TP

.BR ENFILE

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

.LP

.IR "The following sections are informative."

.SH EXAMPLES

None.

.SH "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

\fIgetgrnam\fR()

and

\fIgetgrgid\fR()

whenever possible because it avoids these dependencies.

.SH RATIONALE

None.

.SH "FUTURE DIRECTIONS"

None.

.SH "SEE ALSO"

.IR "\fIendpwent\fR\^(\|)",

.IR "\fIgetgrgid\fR\^(\|)",

.IR "\fIgetgrnam\fR\^(\|)",

.IR "\fIgetlogin\fR\^(\|)"

.P

The Base Definitions volume of POSIX.1\(hy2008,

.IR "\fB<grp.h>\fP"

.SH 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 .