Questions tagged [variadic]

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.

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A Function Applier for Applying Various Algorithms on Nested Container Things in C++

This is a follow-up question for A recursive_replace_if Template Function Implementation in C++, A recursive_copy_if Template Function Implementation in C++, A recursive_count_if Function with Unwrap ...
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Using templates to wrap variardic JNI method calls into type-safe C++ functors

I am working on a project which uses JNI. More than once I fell over the absence of type safety working with the variardic function calls. So I came up with this module. It wraps the variardic JNI ...
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110 views

Meta functions for sequences of exponents of 2

I have implemented some meta functions to create sequence for exponents of 2. I would love to know if there is any way to make the code more optimized. Note: ...
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1answer
44 views

Using vswprintf( … ) to create wchar_t* with variable argument list

I am using c++17 and wide characters. I have created a function to create a wchar_t* using a variable number of parameters ... #include <stdarg.h> // the ...
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1answer
136 views

`zip` operator to iterate on multiple container in a sign

I worked out a zip operator similar to Python's, because I didn't find one in std. It allows to use range-based ...
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44 views

Simplifying a packaged task for a threadpool implementation

I wrote a thread pool where the user can submit jobs through ThreadTask objects. These objects bundle the job priority, the task as a function, and some arbitrary ...
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3answers
596 views

Coalescing lvalue references to std-optionals

I want to coalesce (lvalue references to) optionals of the same type, in C++17: ...
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4k views

`printf` improvement with C++ variadic templates

I am currently working through learning C++'s variadic templates and I wanted to create an example use of them that is less trivial than the one in my book. I decided to create a modification of ...
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3answers
297 views

Encapsulating snprintf to avoid repetition of sizeof

Correct usage of snprintf involves very long and repetitive lines: ...
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1answer
898 views

Max function with variable number of arguments

I find it irritating that in standard C++ I can't do std::max(a, b) = x when it's possible and that it can't handle more than 2 arguments. For the second concern I ...
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127 views

Creating a cache-friendly component system

I am fairly new to c++ and am attempting to write a simple 2D game engine. I am currently working on my object model: a pure component system, similar to that described in the Data Locality chapter in ...
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Racket macro for variadic FFI

I'm working on FFI wrapper for SDL2 library in Racket. The library includes several variadic functions (e.g. SDL_SetError, SDL_LogMessage etc); Racket FFI does not have straight way for importing ...
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1answer
154 views

Replacing MIN and MAX macros with type-safe, recursive templates of variable arity

I'm currently reading Mastering Perl for Bioinformatics; I'm using the book for learning bioinformatics while implementing the code in C++. I came across a situation where I needed to use the minimum ...
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Min function accepting varying number of arguments in C++17

Come across this problem once again in the book The Modern C++ Challenge. 18. Minimum function with any number of arguments Write a function template that can take any number of arguments and returns ...
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245 views

Variadic Datablocks

I would like to have my variadic template class reviewed. First some explanation what it should do: I'm writing an application where I read in blocks of data. I know before i read in the data which ...
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2answers
262 views

C++ wrapper class to mimic a C array's brace initialization

I have an inheritance class that mimics the behavior of C style array's brace initialization by using a class template that has a variadic constructor but the template itself is not a variadic ...
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1answer
189 views

Variadic Functions in NASM Win64 Assembly

Simple variadic function implementation in NASM Assembly. When implemented like I have below: sum.asm ...
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2answers
120 views

Templated string formatting

This function formats a string by replacing every occurrence of '{n}' with the corresponding argument that was passed to the function where n is an index that ...
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3answers
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The perfect function alias

For many years, I have waited for function aliases in C++. They still aren't here. I've been using macros to generate wrapper functions. This is my best attempt at the perfect function alias: ...
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Small Formatting Library

I am learning C++ and currently playing with variadic template functions and formatting string, So here is my small attempt to write a formatting function and provide a simple iostream-like interface ...
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1answer
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Extract from typelist by runtime value

I combined the ideas from this answer and a comment to this question to create a new instance of a type extracted from a type list. The index of the desired type within the type list is provided at ...
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1answer
413 views

Variadic strcat for c++17

On some video from CPPcon, some one said that there should be variadic overload for operator+ as it can solve allocation when there are multiple ...
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Apply a function to each element of a tuple (“map” a tuple)

C++ doesn't (yet) have a 'map' higher-order function, certainly not one which applies to a compile-time sequence of values like a tuple. We have std::transform, and ...
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641 views

Custom variadic min/max/sum functions

I have decided to write my own min max sum functions. I really don't like the ones provided ...
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1answer
729 views

Alternative to integer_sequence trick

I hate working with std::integer_sequence. Each time I want to write a function foo I have to write an another function ...
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1answer
1k views

Generic message system using variadic templates

in my spare time I´m creating a hobby game engine as decided to write some of my systems on my own. As the time passes I´ve decided to start publishing it as a independent libraries for use (so ...
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Generators and Distributions 2.0

In my original question: Generically encapsulating random generators and distributions into a class template I was given some excellent suggestions from two very informative users. I will give a basic ...
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Generically encapsulating random generators and distributions into a class template

I previously had a set of classes in one of my older libraries for working with the random number generators and distributions that was written when Visual Studio 2008 - 2010 were commonplace and ...
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Extending functions to tuples

Intro: Imagine you have defined addition on types A and B with function A add(A,A) and ...
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Determining if two packs are permutations of each other during compile-time

Often we need to find out if two tuples, or two packs in general, are the same as each other up to permutation. If there are no repeat types, then implementing ...
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Variadic templates to generate SQL string

We have this old MFC code here which uses CString and format specifiers to generate an SQL statement and then execute that SQL. Something like this: ...
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Class to unit-test functions, with rudimentary support for testing multi-parameter functions

Recently I read about test-driven-design and decided to try to create a simple unit testing class to begin using this approach. I have not been programming in Python for very long so forgive my ...
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Partial application in C++

Here is my code: ...
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2answers
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Variadic template class that stores a vector of each type given [closed]

I'm exploring the possibility to generalise a class of mine that stores some entities. I like it to be able to keep entities of several type, given as template arguments. To explore the possibilities ...
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66 views

Header-only variadic console output and runtime input validation in C++ using templates

Template IO Module This is a single-file, header-only input validation with two variadic output functions. One output function simply inserts a new line char after every output and the other one ...
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Rotate a given number of variables in-place

A very simple but useful algorithm: rotate the values of a given number of variables in-place to the left so that the first variable gets the value of the second, the second gets the value of the ...
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1answer
534 views

Implementing printf to a string by calling vsnprintf twice

I'm experimenting with writing a dynamic string library in C, and I decided to write an implementation of sprintf. In my code, I call vsnprintf with a buffer of 0 ...
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1answer
101 views

Sleeping and invoking a task in Python 2.X and Python 3.X

I'm writing a program that needs to be compatible for both Python 2.X and Python 3.X. My problem is that, because of the differences between these two versions, I'm duplicating code. ...
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525 views

Variadic templated method to extract values from a table

Is this the correct, most sane way to do variadic templates in C++? All that this function does is to see if gate has a key, if it has, it adds it to a vector of values, if not, it default constructs ...
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A homemade variadic map

A bit of background: some time ago I wrote a piece of code that can be used for memoization with functions taking one parameter. Now I want to extend this to deal with functions with arbitrary number ...
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1answer
765 views

Function with default parameters in any order

Intent Increase code usability/readability of functions with many default parameters while maintaining as much compile time safety as possible. Motivation It is very common to create functions that ...
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917 views

Typesafe scanf-like function with variadic templates

I'm hoping to get some feedback on a function with variadic templates that parses a format string and fills in some parameters whose order and types are based on the characters in the format string. ...
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4answers
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A variadic C function for concatenating multiple strings

I have this function that takes a number \$N\$, and \$N\$ C strings, concatenates and returns the result: ...
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2answers
698 views

Simple JavaScript precondition checking implementation

I am writing a JavaScript application and would like to validate function arguments in many places. Most of these checks will be for correct argument types, or numeric values within specific ranges. ...
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Concatenate two containers, e.g. vector or strings

I'd like to create a function that can concatenate vectors or strings. It must Keep correct order Be optimal This is the solution I came up with: ...
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Call a lua function - the C++ way

I'm not that good when it comes to templates, especially when it comes to variadic templates. I want to show you some code where I use both - templates and variadic templates - to call a lua function. ...
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A function for convenient string concatenation with variadic templates

I wrote this function for string concatenation some time ago. Jo() stands for "Join". The name is shortened on purpose, because this function is used very often. ...
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1answer
358 views

Implementing checksum add without carry in C

I need to write a function in C which performs a checksum using the rule "add without carry". As I understand it, the "add without carry" concept is equivalent to the bitxor operator and given that ...
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444 views

C++ finalizer template

Consider, please, my code of the finalizer template: ...
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1answer
102 views

Invocation list implementation (signals/slots)

This class is mostly an educational exercise for me using some C++11 constructs. I wanted to create something similar to an "invocation list" in C#, i.e., a list of zero or more function objects which ...