Hashmaps vs function2

Hashmaps

Various open addressing hashmap algorithms in C++ (by goossaert)

function2

Improved and configurable drop-in replacement to std::function that supports move only types, multiple overloads and more (by Naios)

Containers Function Functional function-wrapper type-erasure

Source Code

naios.github.io

Docs

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Hashmaps		function2
	Project
-	Mentions	7
257	Stars	523
-	Growth	-
0.0	Activity	4.7
over 2 years ago	Latest Commit	about 2 months ago
C++	Language	C++
MIT License	License	Boost Software License 1.0

The number of mentions indicates the total number of mentions that we've tracked plus the number of user suggested alternatives.
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.

Hashmaps

Posts with mentions or reviews of Hashmaps. We have used some of these posts to build our list of alternatives and similar projects.

We haven't tracked posts mentioning Hashmaps yet.
Tracking mentions began in Dec 2020.

function2

Posts with mentions or reviews of function2. We have used some of these posts to build our list of alternatives and similar projects. The last one was on 2023-03-31.

Callbacks in embedded | heapless environment
7 projects | /r/cpp | 31 Mar 2023

Fixed size function wrappers are not only limited and also a waste of space. Use a configurable function wrapper like fu2 with a stack allocator and set small object optimizer capacity to 0.
Scriptable Headless Player Bots and independent ECS in a Custom UE C++ Server for MMO(RPG)s.
5 projects | /r/unrealengine | 10 Oct 2022
A custom C++ server for the Unreal Engine 5, optimized for MMO(RPG)s.
8 projects | /r/unrealengine | 2 Jun 2022
A simple std::function alternative that never allocates
3 projects | /r/cpp | 17 Oct 2021

std::function wasn't cutting it for me, but I ended up going with fu2::function. It comes with a lot of features (almost too many), but the header size and compile times are comparable to , and it fit my needs pretty well.
Idle: an asynchronous and hot-reloadable C++ dynamic component framework
4 projects | /r/cpp | 15 Sep 2021

Thank you, function2 is also used heavily in Idle as a type-erasure backend for continuable that is the primary asynchronous task abstraction.
Should std::function's move assignment operation be noexcept?
1 project | /r/cpp | 26 Mar 2021
Orthodox C++
2 projects | news.ycombinator.com | 27 Dec 2020

You can write your own std::function, too, nor is it the only STL type that can take a capturing lambda (std::packaged_task for example).
A capturing lambda is just a class with an operator(). It's complicated to do what std::function does, but fully possible.
In fact, custom std::function replacements have better lambda support than std::function itself. Such as unique_function in https://github.com/Naios/function2 which can handle non-copyable lambdas.