linux man page for setgrent

GETGRENT(3)						     Linux Programmer's Manual						       GETGRENT(3)

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  suc-
       cessive 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/.

								    2010-09-20							       GETGRENT(3)