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>
la_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(), thearchive_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 byarchive_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), 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), libarchive(3), tar(5)