SetFunction

change a function vector in a library

SetFunction is a functional way of changing where vectors in a library point. They are changed in such a way that the checksumming process will never falsely declare a library to be invalid.

If you use SetFunction on a function that can be called from interrupts, you are obligated to provide your own arbitration.

SetFunction cannot be used on non-standard libraries like pre-V36 dos.library. Here you must manually Forbid(), preserve all 6 original bytes, set the new vector, SumLibrary(), then Permit().

The function offset is limited to an unsigned 16 bit number. See the notes on MakeLibrary() and MakeFunctions().

library

a pointer to the library to be changed

funcOffset

the offset of the function to be replaced

funcEntry

pointer to new function

oldFunc

pointer to the old function that was just replaced

MakeLibrary(), MakeFunctions()