GETGRNAM(3)		   Linux Programmers Manual		  GETGRNAM(3)



NAME
       getgrnam, getgrnam_r, getgrgid, getgrgid_r - get group file entry

SYNOPSIS
       #include 
       #include 

       struct group *getgrnam(const char *name);

       struct group *getgrgid(gid_t gid);

       int getgrnam_r(const char *name, struct group *gbuf,
		 char *buf, size_t buflen, struct group **gbufp);

       int getgrgid_r(gid_t gid, struct group *gbuf,
		 char *buf, size_t buflen, struct group **gbufp);

DESCRIPTION
       The getgrnam() function returns a pointer to a structure containing the
       broken-out fields of the record in the group database (e.g., the  local
       group file /etc/group, NIS, and LDAP) that matches the group name name.

       The getgrgid() function returns a pointer to a structure containing the
       broken-out  fields of the record in the group database that matches the
       group ID gid.

       The getgrnam_r() and getgrgid_r() functions obtain  the	same  informa
       tion,  but  store the retrieved group structure in the space pointed to
       by gbuf.  This group structure contains pointers to strings, and  these
       strings	are stored in the buffer buf of size buflen.  A pointer to the
       result (in case of success) or NULL (in case no entry was found	or  an
       error occurred) is stored in *gbufp.

       The group structure is defined in  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 */
	   };

       The  maximum needed size for buf can be found using sysconf(3) with the
       argument _SC_GETGR_R_SIZE_MAX.

RETURN VALUE
       The getgrnam() and getgrgid() functions return a  pointer  to  a  group
       structure,  or  NULL  if  the  matching	entry is not found or an error
       occurs.	If an error occurs, errno is set appropriately.  If one  wants
       to  check  errno  after	the  call, it should be set to zero before the
       call.

       The return value may point to static area, and may  be  overwritten  by
       subsequent calls to getgrent(3), getgrgid(), or getgrnam().

       The getgrnam_r() and getgrgid_r() functions return zero on success.  In
       case of error, an error number is returned.

ERRORS
       0 or ENOENT or ESRCH or EBADF or EPERM or ...
	      The given name or gid was not found.

       EINTR  A signal was caught.

       EIO    I/O error.

       EMFILE The maximum number (OPEN_MAX) of files was open already  in  the
	      calling process.

       ENFILE The maximum number of files was open already 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.

NOTES
       The  formulation given above under "RETURN VALUE" is from POSIX.1-2001.
       It does not call "not found" an error,  hence  does  not  specify  what
       value errno might have in this situation.  But that makes it impossible
       to recognize errors.  One might argue that  according  to  POSIX  errno
       should be left unchanged if an entry is not found.  Experiments on var
       ious Unix-like systems shows that lots of  different  values  occur  in
       this  situation: 0, ENOENT, EBADF, ESRCH, EWOULDBLOCK, EPERM and proba
       bly others.

SEE ALSO
       endgrent(3),  fgetgrent(3),  getgrent(3),   getpwnam(3),   setgrent(3),
       group(5)

COLOPHON
       This  page  is  part of release 3.05 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/.



				  2003-11-15			   GETGRNAM(3)