NAME

       endgrent, getgrent, setgrent - group database entry functions

SYNOPSIS

       #include <grp.h>

       void endgrent(void);
       struct group *getgrent(void);
       void setgrent(void);

DESCRIPTION

       The  getgrent()  function  shall return a pointer to a structure containing the broken-out
       fields of an entry in the group database. When first called,  getgrent()  shall  return  a
       pointer to a group structure containing the first entry in the group database. Thereafter,
       it shall return a pointer to a group structure containing the next group structure in  the
       group database, so successive calls may be used to search the entire database.

       An   implementation   that   provides   extended  security  controls  may  impose  further
       implementation-defined restrictions on accessing the group database.  In  particular,  the
       system may deny the existence of some or all of the group database entries associated with
       groups other than those groups associated with the caller and may omit  users  other  than
       the caller from the list of members of groups in database entries that are returned.

       The setgrent() function shall rewind the group database to allow repeated searches.

       The  endgrent()  function  may  be  called  to close the group database when processing is
       complete.

       These functions need not be reentrant. A function that is not required to be reentrant  is
       not required to be thread-safe.

RETURN VALUE

       When  first  called, getgrent() shall return a pointer to the first group structure in the
       group database. Upon subsequent calls it shall return the  next  group  structure  in  the
       group  database.  The getgrent() function shall return a null pointer on end-of-file or an
       error and errno may be set to indicate the error.

       The return value may point to a static area which is overwritten by a subsequent  call  to
       getgrgid(), getgrnam(), or getgrent().

ERRORS

       The getgrent() function may fail if:

       EINTR  A signal was caught during the operation.

       EIO    An I/O error has occurred.

       EMFILE {OPEN_MAX} file descriptors are currently open in the calling process.

       ENFILE The maximum allowable number of files is currently open in the system.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       These  functions  are  provided  due  to their historical usage. Applications should avoid
       dependencies on fields in the group database, whether the database is a  single  file,  or
       where  in  the  file  system  name  space  the  database  resides. Applications should use
       getgrnam() and getgrgid() whenever possible because it avoids these dependencies.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       getgrgid() , getgrnam() , getlogin()  ,  getpwent()  ,  the  Base  Definitions  volume  of
       IEEE Std 1003.1-2001, <grp.h>

COPYRIGHT

       Portions  of  this  text  are  reprinted  and  reproduced in electronic form from IEEE Std
       1003.1, 2003 Edition, Standard for Information Technology  --  Portable  Operating  System
       Interface  (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by
       the Institute of Electrical and Electronics Engineers, Inc and  The  Open  Group.  In  the
       event  of  any  discrepancy  between this version and the original IEEE and The Open Group
       Standard, the original IEEE and The Open Group  Standard  is  the  referee  document.  The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .