archive_util(3) BSD Library Functions Manual 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 result-
ing 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-num-
bered 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 ar-
chive 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 writ-
ten 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-spe-
cific 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.
SEE ALSO
archive_read(3), archive_write(3), libarchive(3), printf(3)
HISTORY
The libarchive library first appeared in FreeBSD 5.3.
AUTHORS
The libarchive library was written by Tim Kientzle <kientzle@acm.org>.
BSD February 2, 2012 BSD
libarchive 3.4.1 - Generated Wed Jan 8 16:51:11 CST 2020