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GETGRENT(3)	       FreeBSD Library Functions Manual		   GETGRENT(3)

NAME
     getgrent, getgrnam, getgrgid, setgroupent,	setgrent, endgrent -- group
     database operations

LIBRARY
     Standard C	Library	(libc, -lc)

SYNOPSIS
     #include <sys/types.h>
     #include <grp.h>

     struct group *
     getgrent(void);

     struct group *
     getgrnam(const char *name);

     struct group *
     getgrgid(gid_t gid);

     int
     setgroupent(int stayopen);

     int
     setgrent(void);

     void
     endgrent(void);

DESCRIPTION
     These functions operate on	the group database file	/etc/group which is
     described in group(5).  Each line of the database is defined by the
     structure group found in the include file <grp.h>:

	   struct group	{
		   char	   *gr_name;	   /* group name */
		   char	   *gr_passwd;	   /* group password */
		   int	   gr_gid;	   /* group id */
		   char	   **gr_mem;	   /* group members */
	   };

     The functions getgrnam() and getgrgid() search the	group database for the
     given group name pointed to by name or the	group id pointed to by gid,
     respectively, returning the first one encountered.	 Identical group names
     or	group gids may result in undefined behavior.

     The getgrent() function sequentially reads	the group database and is
     intended for programs that	wish to	step through the complete list of
     groups.

     All three routines	will open the group file for reading, if necessary.

     The setgroupent() function	opens the file,	or rewinds it if it is already
     open.  If stayopen	is non-zero, file descriptors are left open, signifi-
     cantly speeding functions subsequent calls.  This functionality is	unnec-
     essary for	getgrent() as it doesn't close its file	descriptors by
     default.  It should also be noted that it is dangerous for	long-running
     programs to use this functionality	as the group file may be updated.

     The setgrent() function is	identical to setgroupent() with	an argument of
     zero.

     The endgrent() function closes any	open files.

YP/NIS INTERACTION
     When the yp(4) group database is enabled, the getgrnam() and getgrgid()
     functions use the YP maps ``group.byname''	and ``group.bygid'', respec-
     tively, if	the requested group is not found in the	local /etc/group file.
     The getgrent() function will step through the YP map ``group.byname'' if
     the entire	map is enabled as described in group(5).

RETURN VALUES
     The functions getgrent(), getgrnam(), and getgrgid(), return a pointer to
     the group entry if	successful; if end-of-file is reached or an error
     occurs a null pointer is returned.	 The functions setgroupent() and
     setgrent()	return the value 1 if successful, otherwise the	value 0	is
     returned.	The functions endgrent() and setgrfile() have no return	value.

FILES
     /etc/group	 group database	file

SEE ALSO
     getpwent(3), yp(4), group(5)

HISTORY
     The functions endgrent(), getgrent(), getgrnam(), getgrgid(), and
     setgrent()	appeared in Version 7 AT&T UNIX.  The functions	setgrfile()
     and setgroupent() appeared	in 4.3BSD-Reno.

COMPATIBILITY
     The historic function setgrfile(),	which allowed the specification	of
     alternate password	databases, has been deprecated and is no longer	avail-
     able.

BUGS
     The functions getgrent(), getgrnam(), getgrgid(), setgroupent() and
     setgrent()	leave their results in an internal static object and return a
     pointer to	that object.  Subsequent calls to the same function will mod-
     ify the same object.

FreeBSD	10.1		      September	29, 1994		  FreeBSD 10.1

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | YP/NIS INTERACTION | RETURN VALUES | FILES | SEE ALSO | HISTORY | COMPATIBILITY | BUGS

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