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ARCHIVE_UTIL(3)		    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 rea-
	       son 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  re-
	       turned an error status.
       archive_error_string()
	       Returns	a textual error	message	suitable for display.  The er-
	       ror 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  re-
	       sulting	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,  request-
	       ing   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	exten-
	       sions 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	 indi-
	       cated  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  de-
	       tails 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 ac-
	       cepts a printf-like format string and arguments.	 However,  you
	       should be careful to use	only the following printf format spec-
	       ifiers:	"%c",  "%d", "%jd", "%jo", "%ju", "%jx", "%ld",	"%lo",
	       "%lu", "%lx", "%o", "%u", "%s", "%x", "%%".  Field-width	speci-
	       fiers 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>.

FreeBSD	Ports 14.quarterly     February	2, 2012		       ARCHIVE_UTIL(3)

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