ENDGRENT(3P)              POSIX Programmer's Manual             ENDGRENT(3P)

PROLOG         top

       This manual page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior), or
       the interface may not be implemented on Linux.

NAME         top

       endgrent, getgrent, setgrent — group database entry functions

SYNOPSIS         top

       #include <grp.h>

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

DESCRIPTION         top

       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 thread-safe.

RETURN VALUE         top

       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 application shall not modify the structure to which the return
       value points, nor any storage areas pointed to by pointers within the
       structure. The returned pointer, and pointers within the structure,
       might be invalidated or the structure or the storage areas might be
       overwritten by a subsequent call to getgrgid(), getgrnam(), or

ERRORS         top

       The getgrent() function may fail if:

       EINTR  A signal was caught during the operation.

       EIO    An I/O error has occurred.

       EMFILE All file descriptors available to the process are currently

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

       The following sections are informative.

EXAMPLES         top



       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

RATIONALE         top




SEE ALSO         top

       endpwent(3p), getgrgid(3p), getgrnam(3p), getlogin(3p)

       The Base Definitions volume of POSIX.1‐2008, grp.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) 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 .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the
       source files to man page format. To report such errors, see .

IEEE/The Open Group                 2013                        ENDGRENT(3P)

Pages that refer to this page: grp.h(0p)endpwent(3p)getgrent(3p)getgrgid(3p)getgrnam(3p)setgrent(3p)