libarchive/archive_write_blocksize.3

.\" Copyright (c) 2003-2011 Tim Kientzle
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.\" $FreeBSD$
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.Dd February 2, 2012
.Dt ARCHIVE_WRITE_BLOCKSIZE 3
.Os
.Sh NAME
.Nm archive_write_get_bytes_per_block ,
.Nm archive_write_set_bytes_per_block ,
.Nm archive_write_get_bytes_in_last_block ,
.Nm archive_write_set_bytes_in_last_block
.Nd functions for creating archives
.Sh LIBRARY
Streaming Archive Library (libarchive, -larchive)
.Sh SYNOPSIS
.In archive.h
.Ft int
.Fn archive_write_get_bytes_per_block "struct archive *"
.Ft int
.Fn archive_write_set_bytes_per_block "struct archive *" "int bytes_per_block"
.Ft int
.Fn archive_write_get_bytes_in_last_block "struct archive *"
.Ft int
.Fn archive_write_set_bytes_in_last_block "struct archive *" "int"
.Sh DESCRIPTION
.Bl -tag -width indent
.It Fn archive_write_set_bytes_per_block
Sets the block size used for writing the archive data.
Every call to the write callback function, except possibly the last one, will
use this value for the length.
The default is to use a block size of 10240 bytes.
Note that a block size of zero will suppress internal blocking
and cause writes to be sent directly to the write callback as they occur.
.It Fn archive_write_get_bytes_per_block
Retrieve the block size to be used for writing.
A value of -1 here indicates that the library should use default values.
A value of zero indicates that internal blocking is suppressed.
.It Fn archive_write_set_bytes_in_last_block
Sets the block size used for writing the last block.
If this value is zero, the last block will be padded to the same size
as the other blocks.
Otherwise, the final block will be padded to a multiple of this size.
In particular, setting it to 1 will cause the final block to not be padded.
For compressed output, any padding generated by this option
is applied only after the compression.
The uncompressed data is always unpadded.
The default is to pad the last block to the full block size (note that
.Fn archive_write_open_filename
will set this based on the file type).
Unlike the other
.Dq set
functions, this function can be called after the archive is opened.
.It Fn archive_write_get_bytes_in_last_block
Retrieve the currently-set value for last block size.
A value of -1 here indicates that the library should use default values.
.El
.\" .Sh EXAMPLE
.Sh RETURN VALUES
.Fn archive_write_set_bytes_per_block
and
.Fn archive_write_set_bytes_in_last_block
return
.Cm ARCHIVE_OK
on success, or
.Cm ARCHIVE_FATAL .
.Pp
.Fn archive_write_get_bytes_per_block
and
.Fn archive_write_get_bytes_in_last_block
return currently configured block size
.Po
.Li -1
indicates the default block size
.Pc ,
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_write_set_options 3 ,
.Xr cpio 5 ,
.Xr mtree 5 ,
.Xr tar 5