Can Schedule recognize a function with parameter that has a default value?

[John Young]

I find that it won't recognize  that,

for a function as following

ret fun1(p1,p2=a)

Simulator::schedule(Time duration, &fun1,x) would get me an error

And if I add another function as 

ret fun1(p1) 

I won't get an error.And the command above would invoke the first one. Why is not consistent with c++?

[pdbarnes]

Excellent question. According to cppreference[1] there is only one function, f(int, int), say, declared as f(int, int =1). When the compiler encounters f(2) it silently expands to f(2, 1).

In the context of Schedule however, the EvenImpl caches the function pointer and any explicit arguments:
Schedule(delay, &f, 2) caches the address of f, a two-argument function, and the int value 2. In this translation unit that's fine. The compiler doesn't see the invocation through the function pointer; that happens in a different translation unit, for SimulatorImpl.

Your solution, create an explicit one argument overload for f, is the correct one.

HTH,
Peter
[1] http://en.cppreference.com/w/cpp/language/default_arguments

[John Young]

Ok, thanks.

在 2016年10月11日星期二 UTC+8下午11:27:30，pdbarnes写道：