ON FILL BUFFER block
The ON FILL BUFFER block is used to fill a page of rows into the dynamic array,
based on an offset and a number of rows.
This data block is only used in DISPLAY
ARRAY dialog blocks.
The offset can be retrieved with the FGL_DIALOG_GETBUFFERSTART()
built-in function and the number of rows to provide is defined by the
FGL_DIALOG_GETBUFFERLENGTH() built-in function.
The ON FILL BUFFER block is executed when the runtime system needs data rows to
fill the current page of the list dialog. This can happen before a BEFORE DISPLAY
of a singular DISPLAY ARRAY, or before the BEFORE DIALOG block of
a DIALOG / END DIALOG instruction containing DISPLAY
ARRAY sub-dialogs.
For more details about ON FILL BUFFER usage, see Paged mode of DISPLAY ARRAY.