In computer science, an operator or function is variadic if it can take a varying number of arguments; that is, if its arity is not fixed.
Questions tagged [variadic]
668 questions
4
votes
1 answer
std::tuple<> of one std::shared_ptr<> does not work?
I recently discovered a problem with using std::tuple<> for just one element. I created a class for type erasure and retaining N number of reference counted objects. However the reference counted object is not retained if it is the only one in the…
Aaron Albers
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4
votes
3 answers
C variadic wrapper
To output formatted debug output, I've written a wrapper for vsfprint. Now, I wanted to allocate exactly enough memory for the output buffer, instead of just claiming a random high buffer size (it's a small embedded platform (ESP8266)). For that I…
svenema
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4
votes
3 answers
How to check the type of passed arguments to variadic function
I'm new to variadic templates and for the sake of learning consider the following function
template
T* make_arr(args... arg) {
// Code to check if passed args are of the same type
T* arr = new…
Laith
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1 answer
C++ - deduce parameter pack (variadic template) constructor and copy constructor by enable_if_t
Update:
Thank you, Jamboree.
This is the final struct A.
struct A
{
template>
A(Args &&...args)
{
cout<<'v';
}
template
Caesar
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4
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3 answers
C++ Vector Template Per-Component Operations
I'm rewriting the vector math portion of my project, and I'd like to generalize vectors by their type and number of dimensions. A vector represents an N dimensional vector of type T.
template
struct vector {
T…
Janz
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4
votes
2 answers
Obtaining a pack of packs
This is a very tough one (for me at least). I'll start off by discussing an easier task that I've already solved. ExpandPacks::type is a pack of all packs obtained from taking one type from each pack in Packs.... For…
prestokeys
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4
votes
2 answers
Functional composition with variadic templates
My goal is to get composition of functions working with this exact syntax:
int main() {
Function f([](const std::string& s) {return s.length();});
Function g([](int x) {return x + 0.5;});
Function
prestokeys
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4
votes
1 answer
Does c++0x tuple use the new variadic templates or Boost's macro-fied tuple implementation?
I read it was based on Boost's version, but I wasn't quite sure what that meant when it came down to implementation. I know Boost does their own variadic template, but I would assume c++0x would use its own variadic templates for the new tuple.
Brett Rossier
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4
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1 answer
What is the use of variadic constructor in C++?
Consider following program:
#include
struct Test
{
Test(...)
{
std::cout<<"Variadic constructor\n";
}
};
int main()
{
Test t;
t={3,4,5};
}
I think it is variadic constructor. Does the C++ standard says that…
Destructor
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2 answers
How to expand macro and delete comma
For example I want to write my own printf() alternative, but I have to perform calculations on the variable arguments:
#define log(fmt_string, ...) my_log(fmt_string, pack_args(__VA_ARGS__), __VA_ARGS__)
where pack_args(...) - is a macro too.
How…
Anton Kochkov
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4
votes
1 answer
How to use variadic templates to wrap a variable number of function arguments?
I want to take a variable number of function arguments, and in the function itself, wrap each function argument using a template wrapper class and pass these wrapper classes as arguments to another function.
Say if I have a template class that…
Tony
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4
votes
3 answers
Deduce template parameter pack from function call
I have the following code, where I have a template class, and a type in it, which I would like to use in a separate template function.
template
struct MyClass
{
enum SomeEnum { value0 = -1 };
};
template
simon
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4
votes
1 answer
Pairing compatible types obtained randomly from variadic templates
A Bow can only fire a Missile of type Arrow, Bolt, or Dart (but not a Stone), and can only go with a MissileContainer of type Quiver or Case. A Quiver can only hold Arrows or Bolts, and a Case can only hold Bolts, Darts, or Stones. I've declared…
prestokeys
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4
votes
1 answer
Recursive inheritance with variadic templates
Consider the following code:
#include
struct ActionOption {
virtual void foo(int) const = 0;
};
template struct ActionType;
template <> struct ActionType<0> : ActionOption {
virtual void foo(int) const override {std::cout…
prestokeys
- 4,817
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4
votes
1 answer
stringstream with recursive variadic function?
I want to be able to combine multiple different arguments into a single string using ostringstream. That way I can log the resulting single string without any random issues.
I got this far:
template
void MagicLog(T t)
{
…
ManIkWeet
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