All Questions
613
questions
2
votes
1
answer
120
views
In GCC, inside a lambda, I can get constexpr variable from a non-constexpr template lambda, but not in Visual C++
This code compiles fine in gcc, but fail in Visual C++.
MCVE = https://godbolt.org/z/K7d5PEs65
int main(){
int localVariable=0; //some local variable
auto lamb=[&]<int s>() {
...
- 1,116
0
votes
1
answer
115
views
What is the type of a templated lambda?
The following code tries to create a templated lambda and pass it to a function that calls it. However compilation fails because the type of lambda argument is wrong.
#include <functional>
void ...
- 534
0
votes
1
answer
52
views
Count the number of arguments in generic lambda
I want to create a function that counts the number of arguments in generic lambda functions. SO user "yuri kilochek" has a great solution Count the number of arguments in a lambda but it ...
- 1,654
4
votes
0
answers
160
views
Using a function's argument to produce the type of another function's argument
Since C++20 abbreviated function templates are available for use with placeholder types in parameter list. And one can declare abbreviated function template g with two arguments of same reference type ...
- 19.4k
0
votes
2
answers
74
views
Why code below doesn't compile and what can we do to make it compile in the end?
My code:
#include <functional>
#include <iostream>
template <typename T>
void call_with(std::function<void(T)> f, T val)
{
f(val);
}
int main()
{
auto print = [](int ...
3
votes
1
answer
93
views
Dependent name error in discarded if-constexpr instantiation of function template or generic lambda
From my understanding, dependent name lookup doesn't take place until template instantiation, and template invocations in a discarded if-constexpr statement are not instantiated. As such, I would ...
- 1,269
0
votes
0
answers
62
views
How to cast forwarded arguments to std::invoke conditionally (if it's a certain class) which came from std::forward'ed template (SFINAE?)?
I have created a class member invocation function, which does a delayed call, like:
func = NotifyAll(
&get_file_listener,
&GetFileListener::OnGetFileSuccess, container.c_str(), name....
- 2,190
3
votes
1
answer
72
views
Confusion about type deduction in variadic templates
I have a class with multiple constructors, one being variadic and one taking an additional callable before the variadic arguments. However, the objects I create result in overload resolutions I dont ...
- 51
1
vote
2
answers
175
views
Is it okay to use lambda as a default non-type template argument to generate unique types?
template <auto = [](){}>
struct A;
using unique_1 = A<>;
using unique_2 = A<>;
Is it safe to generate unique types like that or that's some sort of ill-formed behaviour?
- 219
-2
votes
1
answer
76
views
Why can't I use default template parameters while providing a lambda as an argument? [duplicate]
I have a templated function that takes an std::function argument.
#include <iostream>
#include <functional>
template<typename T1, typename T2>
void foo(T1& t, std::function<T2(...
- 1,599
1
vote
3
answers
182
views
How to write typed wrapper for a thread pool?
I have a simple thread pool. It takes tasks and distributes them among threads using round-robin.
The task looks like this
using TaskFn = void (*)(void*);
struct Task {
TaskFn fn;
void* args;
...
- 345
0
votes
1
answer
134
views
deducing general lambdas argument type
I wish to pass void and single argumented direct lambdas to operator call
class My { public: template<typename Callable> operator >> (Callable &&callback){ callback(); return *this;...
- 179
1
vote
1
answer
96
views
SFINAE error in a trait to find the return type of any callable
I am playing around with SFINAE and trying, as an exercise, to get information about "function-like" objects (functions, function pointers, lambdas, and anything overloading the parenthesis ...
- 7,138
1
vote
1
answer
93
views
Inlining lambda calls to template functions
I wish to have a template method, which takes in data and processes it with a lambda function, whatever way the method itself wants to do that. However, I want the lambda function to get inlined so ...
- 199
2
votes
1
answer
95
views
Why I can use a template function as parameter to std::sort but not a template lambda (with member function ptr as template parameter) [duplicate]
Sorry for the long title, as I stated this works:
#include <algorithm>
#include <iostream>
#include <vector>
struct S { int a{}, b{}; };
std::ostream &operator<<(std::...
- 13.1k