Alternative Exception Handling Using the setjmpx Kernel Service

Each exception handler is passed the exception type as a parameter.

For certain types of exceptions, a system call can specify unique exception-handler routines through calls to the setjmpx service. The exception handler routine is saved as part of the stacked saved context.

The exception handler returns a value that can specify any of the following:

• The process should resume with the instruction that caused the exception.
• The process should return to the saved context that is on the top of the stack of contexts.
• The exception handler did not handle the exception.

If the exception handler did not handle the exception, then the next exception handler in the stack of contexts is called. If none of the stacked exception handlers handle the exception, the kernel performs default exception handling. The setjmpx and longjmpx kernel services help implement exception handlers.