Trap Definitions

Note: Traps are the mechanism for programmers to access system functions.
        The three different formats for listing traps are all derived from the Traps
           file which is part of MPW.  This file lists the “official” Mac traps along
           with the names which they have been assigned.  This list is incomplete for
           two main reasons:  some traps were left out by mistake and some were left
           out on purpose because they are subject to change in the future. Generally,
           this information is only of significant interest to programmers.

Unavailable Traps : This lists those “official” traps that for various reasons
           are not available on your combination of hardware and software. They are
           listed in the following format:

$Trap Number in Hex = _TrapName


Note:  The [address] listed in the following two formats may either be the
          the original address as shipped by Apple or may represent changes that 
          were made by various INITs, control panels, etc.


Available Traps (Named): This lists “official” traps available to your 
           machine in the following format:

$Trap Number in Hex = _TrapName [$Address of trap in hex]


Available Traps (UnNamed): This lists unofficial but active traps on your
          machine in the format following.  Since some traps point to the same
          code, one can compare the addresses to determine which are duplicates.
          Duplicate is really not the correct term as Traps which point to the
          same code are generally variations of the original trap.  For example,
           _SetFilType shows the same address at $A043, $A243, and $A443.
          This occurs because, in the case of this type of trap, the $A243
          version means to execute the $A043 command immediately, and the 
          $A443 version means to execute the command asynchronously.  
          Different kinds of traps (e.g. Memory, File, Device, etc.) have similar
          variations with different meanings.

$Trap Number in Hex  [$Address of trap in hex]