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
361
votes
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Why use the params keyword?
I know this is a basic question, but I couldn't find an answer.
Why use it? if you write a function or a method that's using it, when you remove it the code will still work perfectly, 100% as without it. E.g:
With params:
static public int…
MasterMastic
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13 answers
Forward an invocation of a variadic function in C
In C, is it possible to forward the invocation of a variadic function? As in,
int my_printf(char *fmt, ...) {
fprintf(stderr, "Calling printf with fmt %s", fmt);
return SOMEHOW_INVOKE_LIBC_PRINTF;
}
Forwarding the invocation in the manner…
Patrick
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232
votes
6 answers
How to make a variadic macro (variable number of arguments)
I want to write a macro in C that accepts any number of parameters, not a specific number
example:
#define macro( X ) something_complicated( whatever( X ) )
where X is any number of parameters
I need this because whatever is overloaded and can be…
hasen
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212
votes
5 answers
How to use R's ellipsis feature when writing your own function?
The R language has a nifty feature for defining functions that can take a variable number of arguments. For example, the function data.frame takes any number of arguments, and each argument becomes the data for a column in the resulting data table.…
Ryan C. Thompson
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92
votes
10 answers
Is it possible to iterate over arguments in variadic macros?
I was wondering if it is possible to iterate over arguments passed to a variadic macro in C99 or using any GCC extensions ?
For e.g. is it possible to write a generic macro that takes a structure and its fields passed as arguments and prints offset…
vshenoy
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59
votes
6 answers
C++11 variable number of arguments, same specific type
Question is simple, how would I implement a function taking a variable number of arguments (alike the variadic template), however where all arguments have the same type, say int.
I was thinking about something alike this;
void func(int...…
Skeen
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54
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3 answers
How to create a variadic generic lambda?
Since C++14 we can use generic lambdas:
auto generic_lambda = [] (auto param) {};
This basically means that its call operator is templated based on the parameters marked as auto.
The question is how to create a lambda that can accept a variadic…
Drax
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34
votes
4 answers
What is the (...) called in C and C++?
One of the uses of ... is to denote variadic entities in C and C++.
What is its name?
Is it classified as an operator or something else when used that way?
Any other details regarding ...?
Edit: I know the purpose of .... I am asking about its…
Ardent Coder
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33
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4 answers
mixing "exploded" slices and regular parameters in variadic functions
I'm wondering why it's not possible to do the following in go:
func main() {
stuff := []string{"baz", "bla"}
foo("bar", stuff...)
}
func foo(s ...string) {
fmt.Println(s)
}
In my understanding, slice... "explodes" the slice so it can…
Pascal
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30
votes
2 answers
How do I handle an unspecified number of parameters in Scheme?
For example ((fn-stringappend string-append) "a" "b" "c") I know how to handle this (f x y z). But what if there's an unknown number of parameters? Is there any way to handle this kind of problem?
John
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28
votes
8 answers
Creating a string list and an enum list from a C++ macro
In order to make my code shorter and easier to change I want to replace something like
enum{ E_AAA, E_BBB, E_CCC };
static const char *strings{"AAA", "BBB", "CCC" };
With a macro, like INIT(AAA, BBB, CCC); but when I try doing a macro with variable…
Tiago
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28
votes
2 answers
C++11 type trait to differentiate between enum class and regular enum
I'm writing a promotion template alias similar to boost::promote but for C++11.
The purpose of this is to avoid warnings when retrieving arguments from varidic functions. e.g.
template
std::vector MakeArgVectorV(int aArgCount,…
Sam
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25
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3 answers
Does Haskell have variadic functions/tuples?
The uncurry function only works for functions taking two arguments:
uncurry :: (a -> b -> c) -> (a, b) -> c
If I want to uncurry functions with an arbitrary number of arguments, I could just write separate functions:
uncurry2 f (a, b) = f…
fredoverflow
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24
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2 answers
Count of parameters in a parameter pack? Is there a C++0x std lib function for this?
I was just wondering if there was anything in the C++0x std lib already available to count the number of parameters in a parameter pack? I'd like to get rid of the field_count in the code below. I know I can build my own counter, but it just seems…
Brett Rossier
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votes
1 answer
GCC 4.8 is reversing variadic template parameter pack
I just upgraded to GCC 4.8 and some variadic template code no longer compiles correctly. I've created a minimal example below:
#include
#include
template
void something( std::tuple & tup…
Azoth
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