Tribblix: manual page: archive

ARCHIVE_UTIL(3) Introduction to Library Functions ARCHIVE_UTIL(3)

NAME

archive_clear_error, archive_compression, archive_compression_name,
archive_copy_error, archive_errno, archive_error_string,
archive_file_count, archive_filter_code, archive_filter_count,
archive_filter_name, archive_format, archive_format_name,
archive_position, archive_set_error - libarchive utility functions

LIBRARY

Streaming Archive Library (libarchive, -larchive)

SYNOPSIS

#include <archive.h>

void
archive_clear_error(struct archive *);

int
archive_compression(struct archive *);

const char *
archive_compression_name(struct archive *);

void
archive_copy_error(struct archive *, struct archive *);

int
archive_errno(struct archive *);

const char *
archive_error_string(struct archive *);

int
archive_file_count(struct archive *);

int
archive_filter_code(struct archive *, int);

int
archive_filter_count(struct archive *, int);

const char *
archive_filter_name(struct archive *, int);

int
archive_format(struct archive *);

const char *
archive_format_name(struct archive *);

int64_t
archive_position(struct archive *, int);

void
archive_set_error(struct archive *, int error_code, const char *fmt,
...);

DESCRIPTION

These functions provide access to various information about the struct
archive object used in the libarchive(3) library.
archive_clear_error()
Clears any error information left over from a previous call.
Not generally used in client code.
archive_compression()
Synonym for archive_filter_code(a, 0).
archive_compression_name()
Synonym for archive_filter_name(a, 0).
archive_copy_error()
Copies error information from one archive to another.
archive_errno()
Returns a numeric error code (see errno(2)) indicating the
reason for the most recent error return. Note that this can
not be reliably used to detect whether an error has occurred.
It should be used only after another libarchive function has
returned an error status.
archive_error_string()
Returns a textual error message suitable for display. The
error message here is usually more specific than that obtained
from passing the result of archive_errno() to strerror(3).
archive_file_count()
Returns a count of the number of files processed by this
archive object. The count is incremented by calls to
archive_write_header(3) or archive_read_next_header(3).
archive_filter_code()
Returns a numeric code identifying the indicated filter. See
archive_filter_count() for details of the numbering.
archive_filter_count()
Returns the number of filters in the current pipeline. For
read archive handles, these filters are added automatically by
the automatic format detection. For write archive handles,
these filters are added by calls to the various
archive_write_add_filter_XXX() functions. Filters in the
resulting pipeline are numbered so that filter 0 is the filter
closest to the format handler. As a convenience, functions
that expect a filter number will accept -1 as a synonym for the
highest-numbered filter.

For example, when reading a uuencoded gzipped tar archive,
there are three filters: filter 0 is the gunzip filter, filter
1 is the uudecode filter, and filter 2 is the pseudo-filter
that wraps the archive read functions. In this case,
requesting archive_position(a, -1) would be a synonym for
archive_position(a, 2) which would return the number of bytes
currently read from the archive, while archive_position(a, 1)
would return the number of bytes after uudecoding, and
archive_position(a, 0) would return the number of bytes after
decompression.
archive_filter_name()
Returns a textual name identifying the indicated filter. See
archive_filter_count() for details of the numbering.
archive_format()
Returns a numeric code indicating the format of the current
archive entry. This value is set by a successful call to
archive_read_next_header(). Note that it is common for this
value to change from entry to entry. For example, a tar
archive might have several entries that utilize GNU tar
extensions and several entries that do not. These entries will
have different format codes.
archive_format_name()
A textual description of the format of the current entry.
archive_position()
Returns the number of bytes read from or written to the
indicated filter. In particular, archive_position(a, 0)
returns the number of bytes read or written by the format
handler, while archive_position(a, -1) returns the number of
bytes read or written to the archive. See
archive_filter_count() for details of the numbering here.
archive_set_error()
Sets the numeric error code and error description that will be
returned by archive_errno() and archive_error_string(). This
function should be used within I/O callbacks to set system-
specific error codes and error descriptions. This function
accepts a printf-like format string and arguments. However,
you should be careful to use only the following printf format
specifiers: "%c", "%d", "%jd", "%jo", "%ju", "%jx", "%ld",
"%lo", "%lu", "%lx", "%o", "%u", "%s", "%x", "%%". Field-width
specifiers and other printf features are not uniformly
supported and should not be used.

HISTORY

The libarchive library first appeared in FreeBSD 5.3.

AUTHORS