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 num‐

	     ber 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-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