Question

I would like to handle fpu exception on windows, something like:

#include <math.h> #include <fenv.h> #include <stdio.h>  int main() {     double b = 0;     int raised;     feclearexcept (FE_ALL_EXCEPT);     b /= 0;     raised = fetestexcept (FE_OVERFLOW | FE_INVALID);     if (raised & FE_OVERFLOW) { printf('over\n');}     if (raised & FE_INVALID)  { printf('invalid\n');}      return 0; } 

But on windows. I tried reading the MSDN, but the document is not clear at all. I want to do this with Visual Studio compilers, on both x86 and amd64 archs.

I am not interested in translating the exception in C++ – actually, I am not even interested in the FPU exception, only in knowing the FPU state after some computation, like the example above.

== edit ==

Ok, it looks like it is actually much simpler: using _clearfp is enough:

#include <math.h> #include <float.h> #include <stdio.h>  int main() {     double b = 0;     int raised;     raised = _clearfp();     b /= 0;     raised = _clearfp();     if (raised & SW_INVALID)  { printf('invalid\n');}      return 0; } 

Much better than dealing with exceptions, SEH and other non portable stuff 🙂

Answer 1

You can use _statusfp2() to retrieve the floating point status. Beware that 32-bit uses both FPU and SSE instructions. Some sample code:

#include 'stdafx.h' #include <float.h> #include <math.h> #include <assert.h>   int _tmain(int argc, _TCHAR* argv[]) {   unsigned x86;   unsigned sse;   // Test zero-divide   double d = 0;   double v = 1 / d;   _statusfp2(&x86, &sse);   assert(x86 & _EM_ZERODIVIDE);   // Test overflow   v = pow(10, 310.0);   _statusfp2(&x86, &sse);   assert(sse & _EM_OVERFLOW);   return 0; }