.\" Copyright (c) 2003-2011 Tim Kientzle
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.\" $FreeBSD$
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.Dd February 2, 2012
.Dt ARCHIVE_READ_EXTRACT 3
.Os
.Sh NAME
.Nm archive_read_extract ,
.Nm archive_read_extract2 ,
.Nm archive_read_extract_set_progress_callback
.Nd functions for reading streaming archives
.Sh LIBRARY
Streaming Archive Library (libarchive, -larchive)
.Sh SYNOPSIS
.In archive.h
.Ft int
.Fo archive_read_extract
.Fa "struct archive *"
.Fa "struct archive_entry *"
.Fa "int flags"
.Fc
.Ft int
.Fo archive_read_extract2
.Fa "struct archive *src"
.Fa "struct archive_entry *"
.Fa "struct archive *dest"
.Fc
.Ft void
.Fo archive_read_extract_set_progress_callback
.Fa "struct archive *"
.Fa "void (*func)(void *)"
.Fa "void *user_data"
.Fc
.Sh DESCRIPTION
.Bl -tag -compact -width indent
.It Fn archive_read_extract , Fn archive_read_extract_set_skip_file
A convenience function that wraps the corresponding
.Xr archive_write_disk 3
interfaces.
The first call to
.Fn archive_read_extract
creates a restore object using
.Xr archive_write_disk_new 3
and
.Xr archive_write_disk_set_standard_lookup 3 ,
then transparently invokes
.Xr archive_write_disk_set_options 3 ,
.Xr archive_write_header 3 ,
.Xr archive_write_data 3 ,
and
.Xr archive_write_finish_entry 3
to create the entry on disk and copy data into it.
The
.Va flags
argument is passed unmodified to
.Xr archive_write_disk_set_options 3 .
.It Fn archive_read_extract2
This is another version of
.Fn archive_read_extract
that allows you to provide your own restore object.
In particular, this allows you to override the standard lookup functions
using
.Xr archive_write_disk_set_group_lookup 3 ,
and
.Xr archive_write_disk_set_user_lookup 3 .
Note that
.Fn archive_read_extract2
does not accept a
.Va flags
argument; you should use
.Fn archive_write_disk_set_options
to set the restore options yourself.
.It Fn archive_read_extract_set_progress_callback
Sets a pointer to a user-defined callback that can be used
for updating progress displays during extraction.
The progress function will be invoked during the extraction of large
regular files.
The progress function will be invoked with the pointer provided to this call.
Generally, the data pointed to should include a reference to the archive
object and the archive_entry object so that various statistics
can be retrieved for the progress display.
.El
.\"
.Sh RETURN VALUES
Most functions return zero on success, non-zero on error.
The possible return codes include:
.Cm ARCHIVE_OK
(the operation succeeded),
.Cm ARCHIVE_WARN
(the operation succeeded but a non-critical error was encountered),
.Cm ARCHIVE_EOF
(end-of-archive was encountered),
.Cm ARCHIVE_RETRY
(the operation failed but can be retried),
and
.Cm ARCHIVE_FATAL
(there was a fatal error; the archive should be closed immediately).
.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 archive_read 3 ,
.Xr archive_read_data 3 ,
.Xr archive_read_filter 3 ,
.Xr archive_read_format 3 ,
.Xr archive_read_open 3 ,
.Xr archive_read_set_options 3 ,
.Xr archive_util 3 ,
.Xr libarchive 3 ,
.Xr tar 5