NAME¶
archive_read_data
archive_read_data_block
,
archive_read_data_skip
,
archive_read_data_into_fd
—
functions for reading streaming archives
LIBRARY¶
Streaming Archive Library (libarchive, -larchive)
SYNOPSIS¶
#include
<archive.h>
ssize_t
archive_read_data
(
struct
archive *,
void
*buff,
size_t
len);
int
archive_read_data_block
(
struct
archive *,
const void **buff,
size_t *len,
off_t
*offset);
int
archive_read_data_skip
(
struct
archive *);
int
archive_read_data_into_fd
(
struct
archive *,
int
fd);
DESCRIPTION¶
archive_read_data
()
- Read data associated with the header just read. Internally, this is a
convenience function that calls
archive_read_data_block
() and fills any
gaps with nulls so that callers see a single continuous stream of
data.
archive_read_data_block
()
- Return the next available block of data for this entry. Unlike
archive_read_data
(), the
archive_read_data_block
() function
avoids copying data and allows you to correctly handle sparse files, as
supported by some archive formats. The library guarantees that offsets
will increase and that blocks will not overlap. Note that the blocks
returned from this function can be much larger than the block size read
from disk, due to compression and internal buffer optimizations.
archive_read_data_skip
()
- A convenience function that repeatedly calls
archive_read_data_block
() to skip all
of the data for this archive entry. Note that this function is invoked
automatically by
archive_read_next_header2
() if the
previous entry was not completely consumed.
archive_read_data_into_fd
()
- A convenience function that repeatedly calls
archive_read_data_block
() to copy the
entire entry to the provided file descriptor.
RETURN VALUES¶
Most functions return zero on success, non-zero on error. The possible return
codes include:
ARCHIVE_OK
(the operation
succeeded),
ARCHIVE_WARN
(the operation
succeeded but a non-critical error was encountered),
ARCHIVE_EOF
(end-of-archive was
encountered),
ARCHIVE_RETRY
(the operation
failed but can be retried), and
ARCHIVE_FATAL
(there was a fatal error; the
archive should be closed immediately).
archive_read_data
() returns a count of bytes
actually read or zero at the end of the entry. On error, a value of
ARCHIVE_FATAL
,
ARCHIVE_WARN
, or
ARCHIVE_RETRY
is returned.
ERRORS¶
Detailed error codes and textual descriptions are available from the
archive_errno
() and
archive_error_string
() functions.
SEE ALSO¶
tar(1),
libarchive(3),
archive_read(3),
archive_read_extract(3),
archive_read_filter(3),
archive_read_format(3),
archive_read_header(3),
archive_read_open(3),
archive_read_set_options(3),
archive_util(3),
tar(5)