At 8:31 PM +0200 2000/03/18, shay wrote:
>that's why i ask the question in the beginning.
>i can't use hackmaster (i have my reasons).
>i need to do it myself, so i asked what is the best way, so i shouldn't
>break other's traps.
>:-)
>and unfortunately to me - i'm badly care about that.
It's not logically possible without a trap manager like Hackmaster. Here's one example
(of many) why:
1.) A patches trap, saving original trap address for call-through (it's an OS
function).
2.) B patches trap, saving original trap address for call-through (it's A's patch, but
B thinks it's an OS function).
3.) A removes trap, restoring the original trap address (it's an OS function). The
trap is fully restored. But...
4.) B is no longer in the patch chain, and B now has an invalid call-through address
(it's A which just went away). This is a serious problem if, for example, B uses a
callback timer which attempts to call through its saved trap address.
Hackmaster avoids this scenario by removing the responsibility of re-linking the patch
chain from the patcher.
Regards,
Jim Schram
Palm Incorporated
Partner Engineering
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