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man pages section 3: Extended Library Functions, Volume 1

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Updated: Wednesday, July 27, 2022
 
 

archive_read_data (3archive)

Name

archive_read_data - archive_read_data, archive_read_data_block, archive_read_data_skip, functions for reading streaming archives

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(3archive)



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.  Inter-
                   nally, 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 automat-
                   ically 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), AR-
       CHIVE_WARN (the operation succeeded but a non-critical error was
       encountered), ARCHIVE_EOF (end-of-archive was encountered), AR-
       CHIVE_RETRY (the operation failed but can be retried), and AR-
       CHIVE_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, AR-
       CHIVE_WARN, or ARCHIVE_RETRY is returned.

ERRORS
       Detailed error codes and textual descriptions are available from the
       archive_errno() and archive_error_string() functions.


ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:


       +---------------+--------------------+
       |ATTRIBUTE TYPE |  ATTRIBUTE VALUE   |
       +---------------+--------------------+
       |Availability   | library/libarchive |
       +---------------+--------------------+
       |Stability      | Uncommitted        |
       +---------------+--------------------+

SEE ALSO
       tar(1), archive_read(3), archive_read_extract(3), archive_read_fil-
       ter(3), archive_read_format(3), archive_read_header(3), ar-
       chive_read_open(3), archive_read_set_options(3), archive_util(3),
       libarchive(3)



NOTES
       Source code for open source software components in Oracle Solaris can
       be found at https://www.oracle.com/downloads/opensource/solaris-source-
       code-downloads.html.

       This software was built from source available at
       https://github.com/oracle/solaris-userland.  The original community
       source was downloaded from
       https://github.com/libarchive/libarchive/releases/down-
       load/v3.6.1/libarchive-3.6.1.tar.gz.

       Further information about this software can be found on the open source
       community website at http://www.libarchive.org/.



                               February 2, 2012
                                                   ARCHIVE_READ_DATA(3archive)