11/3/71 ARCHIVE (V)
NAME archive (library) file format
SYNOPSIS --
DESCRIPTION The archive command ar is used to combine several
files into one. Its use has three benefits: when
files are combined, the file space consumed by
the breakage at the end of each file (256 bytes
on the average) is saved; directories are smaller
and less confusing; archive files of object pro-
grams may be searched as libraries by the loader
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 is
-147(10), or 177555(8) (it was chosen to be un-
likely to occur anywhere else). The header of
each file is 16 bytes long:
0-7
file name, null padded on the right
8-11
Modification time of the file
12
User ID of file owner
13
file mode
14-15
file size
If the file is an odd number of bytes long, it is
padded with a null byte, but the size in the
header is correct.
Notice there is no provision for empty areas in
an archive file.
FILES --
SEE ALSO ar, ld
DIAGNOSTICS --
BUGS --
OWNER ken, dmr