NAME

       archive_write_open,    archive_write_open_fd,    archive_write_open_FILE,    archive_write_open_filename,
       archive_write_open_memory — functions for creating archives

LIBRARY

       Streaming Archive Library (libarchive, -larchive)

SYNOPSIS

       #include <archive.h>

       int
       archive_write_open(struct archive *,             void *client_data,              archive_open_callback *,
           archive_write_callback *, archive_close_callback *);

       int
       archive_write_open_fd(struct archive *, int fd);

       int
       archive_write_open_FILE(struct archive *, FILE *file);

       int
       archive_write_open_filename(struct archive *, const char *filename);

       int
       archive_write_open_memory(struct archive *, void *buffer, size_t bufferSize, size_t *outUsed);

DESCRIPTION

       archive_write_open()
               Freeze the settings, open the archive, and prepare for writing entries.  This is the most generic
               form  of  this function, which accepts pointers to three callback functions which will be invoked
               by the compression layer to write the constructed archive.

       archive_write_open_fd()
               A  convenience  form   of   archive_write_open()   that   accepts   a   file   descriptor.    The
               archive_write_open_fd()  function  is  safe  for  use  with  tape  drives or other block-oriented
               devices.

       archive_write_open_FILE()
               A  convenience  form  of  archive_write_open()  that  accepts  a  FILE  *  pointer.   Note   that
               archive_write_open_FILE()  is  not  safe for writing to tape drives or other devices that require
               correct blocking.

       archive_write_open_file()
               A deprecated synonym for archive_write_open_filename().

       archive_write_open_filename()
               A convenience form of archive_write_open() that accepts a filename.  A  NULL  argument  indicates
               that  the  output  should be written to standard output; an argument of “-” will open a file with
               that   name.    If   you   have   not   invoked   archive_write_set_bytes_in_last_block(),   then
               archive_write_open_filename()  will  adjust the last-block padding depending on the file: it will
               enable padding when writing to standard output or to a character or block device  node,  it  will
               disable    padding    otherwise.     You    can    override    this    by    manually    invoking
               archive_write_set_bytes_in_last_block()     before     calling     archive_write_open().      The
               archive_write_open_filename()  function  is safe for use with tape drives or other block-oriented
               devices.

       archive_write_open_memory()
               A convenience form of archive_write_open() that accepts a pointer to a block of memory that  will
               receive the archive.  The final size_t * argument points to a variable that will be updated after
               each  write  to  reflect  how  much  of the buffer is currently in use.  You should be careful to
               ensure that this variable remains allocated until after the archive is closed.
       More information about the struct archive object and the overall design of the library can  be  found  in
       the libarchive(3) overview.

CLIENT CALLBACKS

       To  use  this  library,  you  will need to define and register callback functions that will be invoked to
       write data to the resulting archive.  These functions are registered by calling archive_write_open():

             typedef int archive_open_callback(struct archive *, void *client_data)

       The open callback is invoked by archive_write_open().  It should return ARCHIVE_OK if the underlying file
       or data source is successfully opened.  If the open fails, it should call archive_set_error() to register
       an error code and message and return ARCHIVE_FATAL.

             typedef  ssize_t  archive_write_callback(struct archive *,  void *client_data,  const void *buffer,
             size_t length)

       The  write callback is invoked whenever the library needs to write raw bytes to the archive.  For correct
       blocking, each call to the write callback function should translate into a single write(2)  system  call.
       This  is especially critical when writing archives to tape drives.  On success, the write callback should
       return the number of bytes actually written.  On error, the callback should invoke archive_set_error() to
       register an error code and message and return -1.

             typedef int archive_close_callback(struct archive *, void *client_data)

       The close callback is invoked by archive_close when the archive processing  is  complete.   The  callback
       should  return  ARCHIVE_OK  on  success.   On  failure, the callback should invoke archive_set_error() to
       register an error code and message and return ARCHIVE_FATAL.

       Note that if the client-provided write callback function returns a non-zero value,  that  error  will  be
       propagated  back  to  the  caller  through whatever API function resulted in that call, which may include
       archive_write_header(),   archive_write_data(),   archive_write_close(),    archive_write_finish(),    or
       archive_write_free().   The  client callback can call archive_set_error() to provide values that can then
       be retrieved by archive_errno() and archive_error_string().

RETURN VALUES

       These functions return ARCHIVE_OK on success, or ARCHIVE_FATAL.

ERRORS

       Detailed  error  codes  and  textual  descriptions   are   available   from   the   archive_errno()   and
       archive_error_string() functions.

SEE ALSO

       tar(1),     libarchive(3),     archive_write(3),     archive_write_filter(3),    archive_write_format(3),
       archive_write_new(3), archive_write_set_options(3), cpio(5), mtree(5), tar(5)

Debian                                          February 2, 2012                           ARCHIVE_WRITE_OPEN(3)