GETGRENT
Section: Linux Programmer's Manual (3)
Updated: 2010-09-20
NAME
getgrent, setgrent, endgrent - get group file entry
SYNOPSIS
#include <sys/types.h>
#include <grp.h>
struct group *getgrent(void);
void setgrent(void);
void endgrent(void);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
setgrent(),
-
_SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE >= 500 ||
_XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED ||
/* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200809L
getgrent(),
endgrent():
-
_SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE >= 500 ||
_XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
DESCRIPTION
The
getgrent()
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
/etc/group,
NIS, and LDAP).
The first time
getgrent()
is called,
it returns the first entry; thereafter, it returns successive entries.
The
setgrent()
function rewinds to the beginning
of the group database, to allow repeated scans.
The
endgrent()
function is used to close the group database
after all processing has been performed.
The group structure is defined in <grp.h> as follows:
struct group {
char *gr_name; /* group name */
char *gr_passwd; /* group password */
gid_t gr_gid; /* group ID */
char **gr_mem; /* group members */
};
RETURN VALUE
The
getgrent()
function returns a pointer to a
group
structure,
or NULL if there are no more entries or an error occurs.
Upon error,
errno
may be set.
If one wants to check
errno
after the call, it should be set to zero before the call.
The return value may point to a static area, and may be overwritten
by subsequent calls to
getgrent(),
getgrgid(3),
or
getgrnam(3).
(Do not pass the returned pointer to
free(3).)
ERRORS
- EINTR
-
A signal was caught.
- EIO
-
I/O error.
- EMFILE
-
The calling process already has too many open files.
- ENFILE
-
Too many open files in the system.
- ENOMEM
-
Insufficient memory to allocate
group
structure.
- ERANGE
-
Insufficient buffer space supplied.
FILES
- /etc/group
-
local group database file
CONFORMING TO
SVr4, 4.3BSD, POSIX.1-2001.
SEE ALSO
fgetgrent(3),
getgrent_r(3),
getgrgid(3),
getgrnam(3),
getgrouplist(3),
putgrent(3)
COLOPHON
This page is part of release 3.27 of the Linux
man-pages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- FILES
-
- CONFORMING TO
-
- SEE ALSO
-
- COLOPHON
-
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Time: 07:35:27 GMT, March 26, 2013