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[thirdparty/man-pages.git] / man3 / getgrent.3

.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
.\"
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.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
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.\" References consulted:
.\"     Linux libc source code
.\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
.\"     386BSD man pages
.\" Modified Sat Jul 24 19:29:54 1993 by Rik Faith (faith@cs.unc.edu)
.TH GETGRENT 3  1993-04-04 "" "Linux Programmer's Manual"
.SH NAME
getgrent, setgrent, endgrent \- get group file entry
.SH SYNOPSIS
.nf
.B #include <sys/types.h>
.B #include <grp.h>
.sp
.B struct group *getgrent(void);
.sp
.B void setgrent(void);
.sp
.B void endgrent(void);
.fi
.SH DESCRIPTION
The \fBgetgrent\fP()
function returns a pointer to a structure containing
the broken-out fields of a record in the group database
(e.g., the local group file
.IR /etc/group ,
NIS, and LDAP).
The first time it is called
it returns the first entry; thereafter, it returns successive entries.
.PP
The \fBsetgrent\fP() function rewinds to the beginning
of the group database, to allow repeated scans.
.PP
The \fBendgrent\fP() function is used to close the group database
after all processing has been performed.
.PP
The \fIgroup\fP structure is defined in \fI<grp.h>\fP as follows:
.sp
.RS +0.25i
.nf
struct group {
    char   *gr_name;       /* group name */
    char   *gr_passwd;     /* group password */
    gid_t   gr_gid;        /* group ID */
    char  **gr_mem;        /* group members */
};
.fi
.RE
.SH "RETURN VALUE"
The \fBgetgrent\fP() function returns a pointer to a
.I group
structure,
or NULL if there are no more entries or an error occurs.
.LP
Upon error,
.I errno
may be set.
If one wants to check
.I errno
after the call, it should be set to zero before the call.
.SH ERRORS
.TP
.B EINTR
A signal was caught.
.TP
.B EIO
I/O error.
.TP
.B EMFILE
The calling process already has too many open files.
.TP
.B ENFILE
Too many open files in the system.
.TP
.B ENOMEM
.\" not in POSIX
Insufficient memory to allocate group information structure.
.TP
.B ERANGE
Insufficient buffer space supplied.
.SH FILES
.TP
.I /etc/group
local group database file
.SH "CONFORMING TO"
SVr4, 4.3BSD, POSIX.1-2001.
.SH "SEE ALSO"
.BR fgetgrent (3),
.BR getgrent_r (3),
.BR getgrgid (3),
.BR getgrnam (3),
.BR putgrent (3)