SetTrapAddress

SetTrapAddress Install custom code to replace a system routine

#include <OSUtils.h> Operating System Utilities

void SetTrapAddress(trapAddr, trapNum );

long trapAddr ; address of custom code

short trapNum ; the trap to intercept. See TrapWords.

SetTrapAddress changes an element of the trap dispatch table so that

subsequent invocations of that trap will cause execution to go to a specified

SetOSTrapAddress if you know you are running on a 128K ROM or later.

trapAddr is the address of code to handle execution of an Operating System or

Toolbox function. For the 64K ROMs, this value must be less than

64K (you can allocate a 6-byte record in the system heap and fill it

with a jump to your code).

trapNum identifies the ROM routine you wish to replace. See TrapWords for a

list.

Notes: Be sure not to depend on register A5 within your patch. This is because you

may have intercepted a trap used by a desk accessory. Use SetCurrentA5

and SetA5 to be sure you do it right.

Note: Be sure to change all traps back to their original addresses before

your application exits!

The trap dispatcher changed between the 64K and 128K ROMs. For more