I've been experimenting to see if I can do a managed-unmanaged
transition in C++ using the internal call mechanism - using calli to go
straight
into unmanaged code. Does anyone know if it's possible to do it?
I've managed to get the C++ code to do an indirect calli into
an unmanaged function by using C++ function pointers, but I always
run into the problem that the C++ compiler insists on compiling
my unmanaged function into an IL pinvokeimpl method instead of
into a straight undecorated chunk of native executable instructions
- which I believe means my call still ends up going through P/Invoke.
Code snippets...
#pragma unmanaged
int DoubleIt(int x)
{
return 2*x;
}
#pragma managed
int _tmain(void)
{
// this mucking about with w is to stop the compiler optimizing away
// the fptr function pointer altogether and turning what I want to be
// a calli into a hardcoded call. Sometimes the C++ compiler can be just
too
// clever!
int w;
int (*fptr)(int);
w = 34;
if (w<20)
fptr = NULL;
else
fptr = DoubleIt;
// OK - this is it...
int y = fptr(3);
Simon
-----------------------------------------------------------
Simon Robinson
http://www.SimonRobinson.com
-----------------------------------------------------------
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