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.
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⟩.