| NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | FILES | CONFORMING TO | SEE ALSO | COLOPHON | The Linux Programming Interface |
GETGRENT(3) Linux Programmer's Manual GETGRENT(3)
getgrent, setgrent, endgrent - get group file entry
#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
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 */
};
For more information about the fields of this structure, see group(5).
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).)
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.
/etc/group
local group database file
SVr4, 4.3BSD, POSIX.1-2001.
fgetgrent(3), getgrent_r(3), getgrgid(3), getgrnam(3), getgrouplist(3),
putgrent(3), group(5)
This page is part of release 3.32 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/.
2010-10-21 GETGRENT(3)
HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface