Figure 5: MYSEH2.CPP
//==================================================
// MYSEH2 - Matt Pietrek 1997
// Microsoft Systems Journal, January 1997
// FILE: MYSEH2.CPP
// To compile: CL MYSEH2.CPP
//==================================================
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <stdio.h>
EXCEPTION_DISPOSITION
__cdecl
_except_handler(
struct _EXCEPTION_RECORD *ExceptionRecord,
void * EstablisherFrame,
struct _CONTEXT *ContextRecord,
void * DispatcherContext )
{
printf( "Home Grown handler: Exception Code: %08X Exception Flags %X",
ExceptionRecord->ExceptionCode, ExceptionRecord->ExceptionFlags );
if ( ExceptionRecord->ExceptionFlags & 1 )
printf( " EH_NONCONTINUABLE" );
if ( ExceptionRecord->ExceptionFlags & 2 )
printf( " EH_UNWINDING" );
if ( ExceptionRecord->ExceptionFlags & 4 )
printf( " EH_EXIT_UNWIND" );
if ( ExceptionRecord->ExceptionFlags & 8 )
printf( " EH_STACK_INVALID" );
if ( ExceptionRecord->ExceptionFlags & 0x10 )
printf( " EH_NESTED_CALL" );
printf( "\n" );
// Punt... We don't want to handle this... Let somebody else handle it
return ExceptionContinueSearch;
}
void HomeGrownFrame( void )
{
DWORD handler = (DWORD)_except_handler;
__asm
{ // Build EXCEPTION_REGISTRATION record:
push handler // Address of handler function
push FS:[0] // Address of previous handler
mov FS:[0],ESP // Install new EXECEPTION_REGISTRATION
}
*(PDWORD)0 = 0; // Write to address 0 to cause a fault
printf( "I should never get here!\n" );
__asm
{ // Remove our EXECEPTION_REGISTRATION record
mov eax,[ESP] // Get pointer to previous record
mov FS:[0], EAX // Install previous record
add esp, 8 // Clean our EXECEPTION_REGISTRATION off stack
}
}
int main()
{
_try
{
HomeGrownFrame();
}
_except( EXCEPTION_EXECUTE_HANDLER )
{
printf( "Caught the exception in main()\n" );
}
return 0;
}