_gtDispBegin()
 Begin buffering screen output
------------------------------------------------------------------------------
 C Prototype

     #include "gt.api"
     ERRCODE _gtDispBegin(void)

 Returns

     _gtDispBegin() returns zero if successful.  Any other value indicates an
     error.

 Description

     _gtDispBegin() informs the CA-Clipper display system of the start of a
     series of display operations that are to be buffered.  Display output
     that occurs after _gtDispBegin(), but before _gtDispEnd(), accumulates
     in internal buffers.  All screen updates are performed after
     _gtDispEnd().  This can enhance the performance of applications with
     complex screen displays.

     _gtDispBegin() and _gtDispEnd() calls are optional.

 Notes

     .  Nested calls:  _gtDispBegin() calls are nested internally.  If
        you issue several _gtDispBegin() calls, buffering occurs until you
        issue a corresponding number of _gtDispEnd() calls.

     .  Guaranteed operations:  Display updates performed between
        _gtDispBegin() and _gtDispEnd() are not guaranteed to be buffered.
        Some updates may become visible before _gtDispEnd() is called.
        However, all updates are guaranteed to be visible after the closing
        call to _gtDispEnd().

     .  Terminal operations:  CA-Clipper terminal input operations
        such as INKEY() and READ should not be performed between
        _gtDispBegin() and _gtDispEnd().  Doing this may cause input or
        display output to be lost.

     .  Incompatible operations:  Display output other than by the
        CA-Clipper display functions (e.g., by add-on libraries or by DOS via
        the OUTSTD() function) may not be compatible with _gtDispBegin() and
        _gtDispEnd().  Output may be lost.

 Examples

     .  This example buffers screen output, updates the screen, then
        displays the buffered screen output:

        #include "gt.api"
        .
        .
        .
           _gtDispBegin();      // Start screen buffering

           _gtSetPos(10, 10);
           _gtWrite( "A display update", 17 );

           _gtSetPos(11, 10)
           _gtWrite( "Another display update", 22 )

           _gtDispEnd()         // Display buffered screen data
        .
        .
        .

 Files  Library is CLIPPER.LIB, header file is Gt.api.