User-Mode Exception Handling

Exceptions that occur in a user-mode process and are not automatically handled by the kernel cause the user-mode process to be signaled. If the process is in a state in which it cannot take the signal, it is terminated and the information logged. Kernel routines can install user-mode exception handlers that catch exceptions before they are signaled to the user-mode process.

The uexadd and uexdel kernel services allow system-wide user-mode exception handlers to be added and removed.

The most recently registered exception handler is the first called. If it cannot handle the exception, the next most recent handler on the list is called, and this second handler attempts to handle the exception. If this attempt fails, successive handlers are tried, until the default handler is called, which generates the signal.

Additional information about the exception can be obtained by using the getexcept kernel service.