Re: Function overloading question

From:
Victor Bazarov <v.bazarov@comcast.invalid>
Newsgroups:
comp.lang.c++
Date:
Thu, 05 Dec 2013 07:15:20 -0500
Message-ID:
<l7pqou$3jk$1@dont-email.me>
On 12/5/2013 5:40 AM, blaz.bratanic@gmail.com wrote:

#include <iostream>
#include <vector>
#include <list>

template <typename T>
void foo(T a) {
     std::cout << "General" << std::endl;
}

template <typename T>
void foo(std::vector<T> a) {
     std::cout << "Vector" << std::endl;
}

int main() {
     std::vector<int> v = {1,2,3};
     foo(v); // vector

     std::list<int> l = {1,2,3};
     foo(l); // general
}

Could someone explain does the call to foo not result in an ambiguous call?


Two function templates against which to check each call. Both templates
have the type deduction context from the standard ones, which means that
deduction is not going to fail. But even if it would fail, the failure
is not an error, and it would pick another template. Ambiguity exists
in overloading functions, not function templates, IIUIC.

Probably the question is, why the compiler prefers
foo<int> over foo<std::vector<int>>?


The rule is to prefer a more specialized version, IIRC. foo<int> is
more specialized (more limited) than foo<T> with T==std::vector<int>.
BTW, what output do you get?

V
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