Why cast unused return values to void?

Question

int fn();

void whatever()
{
    (void) fn();
}

Is there any reason for casting an unused return value to void, or am I right in thinking it\'s a c

Answer 1

Also when verifying your code complies to MISTA (or other) standards, automatic tools such as LDRA will not allow you to call a function that has a return type without having it return a value unless you explicitly cast the returned value to (void)