SetUnhandledExceptionFilter
The SetUnhandledExceptionFilter
function lets an application supersede the top-level exception handler that
Win32 places at the top of each thread and process.
After calling
this function, if an exception occurs in a process that is not being debugged,
and the exception makes it to the Win32 unhandled exception filter, that filter
will call the exception filter function specified by the lpTopLevelExceptionFilter
parameter.
LPTOP_LEVEL_EXCEPTION_FILTER
SetUnhandledExceptionFilter(
|
LPTOP_LEVEL_EXCEPTION_FILTER lpTopLevelExceptionFilter |
// exception filter
function |
|
); |
|
Parameters
lpTopLevelExceptionFilter
Supplies the
address of a top-level exception filter function that will be called whenever
the UnhandledExceptionFilter
function gets control, and the process is not being debugged. A value of
NULL for this parameter specifies default handling within UnhandledExceptionFilter.
The filter function has syntax congruent to that of UnhandledExceptionFilter:
It takes a single parameter of type LPEXCEPTION_POINTERS, and returns a
value of type LONG. The filter function should return one of the
following values:
|
Value |
Meaning |
|
EXCEPTION_EXECUTE_HANDLER |
Return from
UnhandledExceptionFilter
and execute the associated exception handler. This usually results in process
termination. |
|
EXCEPTION_CONTINUE_EXECUTION |
Return from
UnhandledExceptionFilter and continue execution from the point of the
exception. Note that the filter function is free to modify the continuation
state by modifying the exception information supplied through its LPEXCEPTION_POINTERS
parameter. |
|
EXCEPTION_CONTINUE_SEARCH |
Proceed
with normal execution of UnhandledExceptionFilter . That means obeying
the SetErrorMod flags, or invoking the Application Error pop-up
message box. |
Return Values
The SetUnhandledExceptionFilter
function returns the address of the previous exception filter established with
the function. A NULL return value means that there is no current top-level
exception handler.
Remarks
Issuing SetUnhandledExceptionFilter
replaces the existing top-level exception filter for all existing and all
future threads in the calling process.
The exception
handler specified by lpTopLevelExceptionFilter is executed in the
context of the thread that caused the fault. This can affect the exception
handler s ability to recover from certain exceptions, such as an invalid stack.
See Also