ARCHIVE_READ_DATA(3) Introduction to Library Functions ARCHIVE_READ_DATA(3)
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(), 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),
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)illumos February 2, 2012 illumos
