int32 GetCelDataBufferSize(CCB *cel)
The return value is the size needed for the buffer, and not necessarily the size of the buffer currently attached to the cel. For example, using this function on a SubRect cel would return the size needed for the sub-rectangle, not the size currently used by the full-size source data attached to the cel.
This function can be called when the cel has no buffer yet, providing that the CCB_CCBPRE flag is set. In this sense, it can be useful for calculating how big a data buffer to allocate.
This function exists primarily to support library internals, but may be useful for applications as well.