All Questions
14 questions
0
votes
3
answers
148
views
Why I need default sum function, for a variadic template sum?
I want to calculate the sum of any number of arguments given to function sum. Assuming that integers given to the function will satisfy operator+.
If I comment out the function sum() (the one having ...
- 89
2
votes
1
answer
172
views
Point of Instantiation for function templates
I am learning about templates in C++. In particular, i read about POIs. So i am trying out(by reading and writing) different examples. One such example which is not clear to me is given below:
...
1
vote
2
answers
408
views
Calling undeclared function template from inside another function template
I am learning about templates in C++ and so trying out different examples. One such example whose output i am unable to understand is given below:
template<typename T> void func(T p) {
g<T>...
2
votes
2
answers
514
views
Unresolved overloaded function type in gcc
I am trying to pass a function template as an argument to another function as seen in the example below.
#include <iostream>
template <typename T>
decltype(auto) foo(T t)
{
return ...
- 973
2
votes
1
answer
57
views
Stringify a recursive `std::vector<std::vector<...>>` without using partial template function specialization
I seek (for example) to stringify a vector of vectors of ... (with arbitrarily deep nesting).
I tried the following:
#include <iostream>
#include <sstream>
#include <vector>
...
- 6,949
1
vote
2
answers
199
views
Function template specialization with const ref arguments
The following code compiles fine.
#include <iostream>
struct rgb8{
uint8_t r() const {return 0;};
};
template<typename L, typename P>
L pixelToLevel(P p) {
return static_cast<...
- 6,949
2
votes
2
answers
276
views
Forwarding wrapper using `std::enable_if` failing
I am trying to create a forwarding wrapper function which times the call of a function in c++14. There are 2 types I need to deal with,
one is timing a function which doesn't return a value, and
...
4
votes
1
answer
2k
views
Why is my function template specialization rejected by VS2017 and not by VS2015?
I have a trait class that associates types to integer values.
struct traits
{
private:
template<int ID> struct type_impl {};
template<> struct type_impl<1> { using type = ...
10
votes
1
answer
463
views
SFINAE : Delete a function with the same prototype
I wonder what is the difference between this code that works :
#include <type_traits>
#include <iostream>
template<typename T> using is_ref = std::enable_if_t<std::...
- 4,048
2
votes
2
answers
209
views
function overloading with std::function and generic lambdas: std::string preferred over int
When trying to compiling this, suprisingly, it gives an error because the auto parameter of the lambda function has been resolved to std::string, and the compiler doesn't know how to convert std::...
- 12.2k
8
votes
1
answer
1k
views
Passing (partially) templated template function as std::function(or function pointer)
#include <vector>
#include <functional>
template<class F>
class Foo
{
public:
template <class T>
void std_function(std::function<F(std::vector<T>)> functor)...
- 1,035
24
votes
4
answers
15k
views
How do you deduce the size of a std::array?
In the following code:
template<size_t N>
int b(int q, const std::array<int, N>& types)
{
int r = q;
for (int t : types)
{
r = r + t;
}
return r;
}
int ...
- 5,842
5
votes
3
answers
3k
views
Function parameter type using decltype
Note: the example provided in this question is not production code and has no sense at all. It is just there to illustrate my problem.
I was testing the possibilities of decltype, especially if it is ...
- 1,217
1
vote
3
answers
169
views
Disallow function template instantiation with iterator parameter
I have a function template which takes a templated parameter:
template <class R>
RefT<R> make_ref(R& res) {
return RefT<R>(&res);
}
I either want to prevent R from ...
- 1,062