NSetTrapAddress

NSetTrapAddress Install custom code to replace a system routine

#include <OSUtils.h> Operating System Utilities

void NSetTrapAddress(trapAddr, trapNum, trapType );

long trapAddr ; address of custom code

short trapNum ; the trap to intercept. See TrapWords.

short trapType ; 0= OS trap; 1=Toolbox trap

NSetTrapAddress changes an element of the trap dispatch table so that

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

address. Use this function (and not SetTrapAddress) if your application

will run in a Mac equipped with a ROM version later than the 64K ROMs (see

trapAddr is the address of some code to handle execution of an Operating

System or Toolbox function.

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

list.

trapType differentiates between traps by type, since the 128K ROMs use two

separate trap dispatch tables. This must be one of:

OSTrap (0) Operating System trap

ToolTrap (1) Toolbox trap

Notes: There is a new interface to this routine, consisting of the calls

require the specification of the trap type as a parameter.

NSetTrapAddress is used mostly by assembly-language programers . It

is most often used in device drivers of INIT code, rather an by an

application.

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

Referenced by (12):