Question

I would like to make sure that this method call is correct. I have three arguments, and one defaults to a null QString.

double funcApply(double* param, QString expr=NULL);

and the call is

funcApply(param);

In function body, I test whether second argument expr is NULL or not, and proceed accrodingly. Will this call behave as expected, or misbehave?

Thanks and regards.

Answer 1

It depends on what you expect it to behave like.

Technically, expr will not be NULL since it’s not a pointer, but its contents will be empty. (assuming you mean QString).

Of course, if you have something like #define QString char*, then expr will be NULL, but I doubt you have that.