.\"	@(#)ar.5	6.1 (Berkeley) 5/15/85
.\"
.TH AR 5  "May 15, 1985"
.AT 3
.SH NAME
ar \- archive (library) file format
.SH SYNOPSIS
.B #include <ar.h>
.SH DESCRIPTION
.PP
The archive command
.I ar
combines several files into one.
Archives are used mainly as libraries to be searched by the link-editor
.I ld.
.PP
A file produced by
.I ar
has a magic string 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:
.RS
.PP
.nf
.ta \w'#define 'u +\w'SARMAG 'u
.ec %
.so /usr/include/ar.h
.ec \
.fi
.RE
.LP
The name is a blank-padded string.
The
.I ar_fmag
field contains ARFMAG to help verify the presence of a header.
The other fields are left-adjusted, blank-padded numbers.
They are decimal except for
.IR ar_mode ,
which is octal.
The date is the modification date of the file
at the time of its insertion into the archive.
.PP
Each file begins on a even (0 mod 2) boundary;
a new-line is inserted between files if necessary.
Nevertheless the size given reflects the
actual size of the file exclusive of padding.
.PP
There is no provision for empty areas in an archive file.
.PP
The encoding of the header is portable across machines.
If an archive contains printable files, the archive itself is printable.
.SH "SEE ALSO"
ar(1), ld(1), nm(1)
.SH BUGS
File names lose trailing blanks.
Most software dealing with archives takes even
an included blank as a name terminator.