unixdev.net


Switch to SpeakEasy.net DSL

The Modular Manual Browser

Home Page
Manual: (v7man)
Page:
Section:
Apropos / Subsearch:
optional field

AR(5)                         File Formats Manual                        AR(5)



NAME
       ar - archive (library) file format

SYNOPSIS
       #include <&lt;ar.h>&gt;

DESCRIPTION
       The  archive command ar is used to combine several files into one.  Ar-
       chives are used mainly as libraries to be searched by  the  link-editor
       ld.

       A  file produced by ar has a magic number at the start, followed by the
       constituent files, each preceded by a file header.   The  magic  number
       and header layout as described in the include file are:

              /* Header describing `ar' archive file format.
                 Copyright (C) 1996-2016 Free Software Foundation, Inc.
                 This file is part of the GNU C Library.

                 The GNU C Library is free software; you can redistribute it and/or
                 modify it under the terms of the GNU Lesser General Public
                 License as published by the Free Software Foundation; either
                 version 2.1 of the License, or (at your option) any later version.

                 The GNU C Library is distributed in the hope that it will be useful,
                 but WITHOUT ANY WARRANTY; without even the implied warranty of
                 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
                 Lesser General Public License for more details.

                 You should have received a copy of the GNU Lesser General Public
                 License along with the GNU C Library; if not, see
                 <http://www.gnu.org/licenses/>;.  */

              #ifndef _AR_H
              #define _AR_H 1

              #include <sys/cdefs.h>

              /* Archive files start with the ARMAG identifying string.  Then follows a
                 `struct ar_hdr', and as many bytes of member file data as its `ar_size'
                 member indicates, for each member file.  */

              #define ARMAG "!<arch>0/* String that begins an archive file.  */
              #define SARMAG8/* Size of that string.  */

              #define ARFMAG"`0/* String in ar_fmag at end of each header.  */

              __BEGIN_DECLS

              struct ar_hdr
                {
                  char ar_name[16];/* Member file name, sometimes / terminated. */
                  char ar_date[12];/* File date, decimal seconds since Epoch.  */
                  char ar_uid[6], ar_gid[6];/* User and group IDs, in ASCII decimal.  */
                  char ar_mode[8];/* File mode, in ASCII octal.  */
                  char ar_size[10];/* File size, in ASCII decimal.  */
                  char ar_fmag[2];/* Always contains ARFMAG.  */
                };

              __END_DECLS

              #endif /* ar.h */

       The  name  is  a  null-terminated  string;  the  date is in the form of
       time(2); the user ID and group ID are numbers; the mode is a  bit  pat-
       tern per chmod(2); the size is counted in bytes.

       Each  file  begins  on a word boundary; a null byte is inserted between
       files if necessary.  Nevertheless the size given  reflects  the  actual
       size of the file exclusive of padding.

       Notice there is no provision for empty areas in an archive file.

SEE ALSO
       ar(1), ld(1), nm(1)

BUGS
       Coding user and group IDs as characters is a botch.



                                                                         AR(5)