You can ignore my previous question about Heap Error 203. I have discovered the variable ReturnNilIfGrowHeapFails which controls the behavior of New. It is not mentioned in the RTL manual, but it is mentioned in the Programmer's Guide. I had not read far enough in Chapter 8, which at first reading seemed to be entirely concerned with the sizes of the various data types.
The description of New in the RTL manual simply states that New returns nil if space is not available. It does not say that this feature defaults to off, and has to be turned on by the program.
Frank