Is short circuit evaluation a language feature in C/C++ or compiler implementation

I'm wondering if short circuit evaluation of

long param = 0;if ( functAWithSideEffects(&param) || funcBWithSideEffects(&param) )

Can be relied on. For example, if funcAWithSideEffects returns true, will the compiler evaluation funcBWithSideEffects? Is short circuit evaluation a language feature or a compiler implementation detail?