ar.5

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 5 代码 · 共 61 行

.TH ar 5 RISC
.SH Name
ar \- archive (library) file format
.SH Syntax
.B #include <ar.h>
.SH Description
The archive command,
.PN ar ,
combines several files into one.
Archives are used mainly as libraries to be searched by the link-editor,
.PN ld .
.PP
A file produced by
.PN 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:
.EX
.ta \w'#define 'u +\w'SARMAG 'u
#define	ARMAG	"!<arch>\\n"
#define	SARMAG	8

#define	ARFMAG	"`\\n"

struct ar_hdr {
	char	ar_name[16];
	char	ar_date[12];
	char	ar_uid[6];
	char	ar_gid[6];
	char	ar_mode[8];
	char	ar_size[10];
	char	ar_fmag[2];
};
.EE
.PP
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 an even (0 mod 2) boundary;
a new-line is inserted between files if necessary.
The size given reflects the
actual size of the file exclusive of padding.
.PP
Provisions are not made 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 Restrictions
A filename loses trailing blanks.  Most software dealing with archives 
takes an included blank as a name terminator.
.SH See Also
ar(1), ld(1), nm(1)