.\" Copyright (c) 2003-2011 Tim Kientzle
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.Dd February 2, 2012
.Dt ARCHIVE_READ_FORMAT 3
.Os
.Sh NAME
.Nm archive_read_support_format_7zip ,
.Nm archive_read_support_format_all ,
.Nm archive_read_support_format_ar ,
.Nm archive_read_support_format_by_code ,
.Nm archive_read_support_format_cab ,
.Nm archive_read_support_format_cpio ,
.Nm archive_read_support_format_empty ,
.Nm archive_read_support_format_iso9660 ,
.Nm archive_read_support_format_lha ,
.Nm archive_read_support_format_mtree,
.Nm archive_read_support_format_rar,
.Nm archive_read_support_format_raw,
.Nm archive_read_support_format_tar ,
.Nm archive_read_support_format_xar ,
.Nm archive_read_support_format_zip
.Nd functions for reading streaming archives
.\"
.Sh LIBRARY
Streaming Archive Library (libarchive, -larchive)
.Sh SYNOPSIS
.In archive.h
.Ft int
.Fn archive_read_support_format_7zip "struct archive *"
.Ft int
.Fn archive_read_support_format_all "struct archive *"
.Ft int
.Fn archive_read_support_format_ar "struct archive *"
.Ft int
.Fn archive_read_support_format_by_code "struct archive *" "int"
.Ft int
.Fn archive_read_support_format_cab "struct archive *"
.Ft int
.Fn archive_read_support_format_cpio "struct archive *"
.Ft int
.Fn archive_read_support_format_empty "struct archive *"
.Ft int
.Fn archive_read_support_format_iso9660 "struct archive *"
.Ft int
.Fn archive_read_support_format_lha "struct archive *"
.Ft int
.Fn archive_read_support_format_mtree "struct archive *"
.Ft int
.Fn archive_read_support_format_rar "struct archive *"
.Ft int
.Fn archive_read_support_format_raw "struct archive *"
.Ft int
.Fn archive_read_support_format_tar "struct archive *"
.Ft int
.Fn archive_read_support_format_xar "struct archive *"
.Ft int
.Fn archive_read_support_format_zip "struct archive *"
.\"
.Sh DESCRIPTION
.Bl -tag -compact -width indent
.It Xo
.Fn archive_read_support_format_7zip ,
.Fn archive_read_support_format_ar ,
.Fn archive_read_support_format_cab ,
.Fn archive_read_support_format_cpio ,
.Fn archive_read_support_format_iso9660 ,
.Fn archive_read_support_format_lha ,
.Fn archive_read_support_format_mtree ,
.Fn archive_read_support_format_rar ,
.Fn archive_read_support_format_raw ,
.Fn archive_read_support_format_tar ,
.Fn archive_read_support_format_xar ,
.Fn archive_read_support_format_zip
.Xc
Enables support---including auto-detection code---for the
specified archive format.
For example,
.Fn archive_read_support_format_tar
enables support for a variety of standard tar formats, old-style tar,
ustar, pax interchange format, and many common variants.
.It Fn archive_read_support_format_all 
Enables support for all available formats except the
.Dq raw
format (see below).
.It Fn archive_read_support_format_by_code
Enables a single format specified by the format code.
This can be useful when reading a single archive twice;
use
.Fn archive_format
after reading the first time and pass the resulting code
to this function to selectively enable only the necessary
format support.
Note:  In statically-linked executables, this will cause
your program to include support for every format.
If executable size is a concern, you may wish to avoid
using this function.
.It Fn archive_read_support_format_empty
Enables support for treating empty files as empty archives.
Because empty files are valid for several different formats,
it is not possible to accurately determine a format for
an empty file based purely on contents.
So empty files are treated by libarchive as a distinct
format.
.It Fn archive_read_support_format_raw 
The
.Dq raw
format handler allows libarchive to be used to read arbitrary data.
It treats any data stream as an archive with a single entry.
The pathname of this entry is
.Dq data ;
all other entry fields are unset.
This is not enabled by
.Fn archive_read_support_format_all
in order to avoid erroneous handling of damaged archives.
.El
.\" .Sh EXAMPLE
.Sh RETURN VALUES
These functions return
.Cm ARCHIVE_OK
on success, or
.Cm ARCHIVE_FATAL .
.\"
.Sh ERRORS
Detailed error codes and textual descriptions are available from the
.Fn archive_errno
and
.Fn archive_error_string
functions.
.\"
.Sh SEE ALSO
.Xr tar 1 ,
.Xr libarchive 3 ,
.Xr archive_read_data 3 ,
.Xr archive_read_filter 3 ,
.Xr archive_read_set_options 3 ,
.Xr archive_util 3 ,
.Xr tar 5
.Sh BUGS
Many traditional archiver programs treat
empty files as valid empty archives.
For example, many implementations of
.Xr tar 1
allow you to append entries to an empty file.
Of course, it is impossible to determine the format of an empty file
by inspecting the contents, so this library treats empty files as
having a special
.Dq empty
format.
.Pp
Using the
.Dq raw
handler together with any other handler will often work
but can produce surprising results.