Hi the list I write a function MyFunc. To optimize it, I write a C function MyFuncC then a function MyFunc2 that call .C(?MyFuncC?,?.) The two functions MyFunc and MyFunc2 seem to behave exactly the same way (they give the same results). But when I test MyFunc2 several times (around 20), R crash. This is not link to a specific example since if I test MyFunc2 on the same example several time, I still get a crash. Any idea of what can cause this kind of error (or even how can I diagnose the problem)? And how I can correct it? Sincerely Christophe