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.   This  does  not  alter  the  default
               archive padding.

       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.  This function
               will disable padding unless you have specifically set the block size.
       More information about the struct archive object and the overall design of the library can  be  found  in
       the libarchive(3) overview.

       Note  that the convenience forms above vary in how they block the output.  See archive_write_blocksize(3)
       if you need to control the block size used for writes or the end-of-file padding behavior.

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  la_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_blocksize(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)