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)