.TH AR 5 
.SH NAME
ar \- archive (library) file format
.SH SYNOPSIS
.B #include <ar.h>
.SH DESCRIPTION
The archive command
.I ar
is used to combine 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 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:
.RS
.PP
.nf
.ta \w'#define 'u +\w'ARMAG 'u
#define	ARMAG	0177545
struct	ar_hdr {
	char	ar_name[14];
	long	ar_date;
	char	ar_uid;
	char	ar_gid;
	int	ar_mode;
	long	ar_size;
};
.fi
.RE
.LP
The name is a null-terminated string; the date is in the
form of
.IR time (2);
the user ID and group ID are numbers; the mode is a bit pattern
per
.IR chmod (2);
the size is counted in bytes.
.PP
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.
.PP
Notice there is no provision for empty areas in an archive
file.
.SH "SEE ALSO"
ar(1), ld(1), nm(1)
.SH BUGS
Coding user and group IDs as characters is a botch.