Hey Why do I need headers files in c++ code when

Question

C / C++

Jacob

Hey Why do I need headers files in c++ code when

creating non library program? does it possible to import namespace without headers?

0

14.11.2024

12 ответов

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Jacob Автор вопроса

main.cpp int main() { foo::hello(); } foo.cpp namespace foo { void hello() { } } Currently I must create foo.h and include it to use foo::hello in main.cpp (VSCode, Clangd, Clang)

0

1 месяц назад

Pavel

Jacob
main.cpp int main() { foo::hello(); } foo.cpp ...

You can forward-declare in your cpp file, basically add the content of your *.h file to the target cpp. However it would result in code duplication as you would need to copy this code around everywhere, and if you need to change something, change it everywhere. Basically header files are the solution to this problem of duplication.

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1 месяц назад

Jacob Автор вопроса

Pavel
You can forward-declare in your cpp file, basicall...

I'm coming from rust and there I don't need headers I just import the namespace / module I feel like I'm writing headers in c++ for no reason it's just CLI app it would be cool if it's generated automatically

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1 месяц назад

Pavel

Jacob
I'm coming from rust and there I don't need header...

If you are writing something small that doesn't require fast compile times, you can move definitions of your functions to the header, just make sure you mark everything global (functions and variables) as inline. Though if it grows big, that could hit compilation and linking times hard.

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1 месяц назад

Thomas

Jacob
main.cpp int main() { foo::hello(); } foo.cpp ...

You don't need headers really

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1 месяц назад

Thomas

Pavel
If you are writing something small that doesn't re...

Стикер

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1 месяц назад

Pavel

Don't know about that, every compilation would recompile everything in a single thread, since there's only one translation unit. There are much smaller projects that can compile for minutes even without this

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1 месяц назад

Thomas

Pavel
Don't know about that, every compilation would rec...

Стикер

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1 месяц назад

Thomas

Pavel
Don't know about that, every compilation would rec...

Molly Rocket (Casey) does single translation unit for most of his projects, and he claims he can build all the code they have in like 10 seconds (>500kLoC), across all projects Zig is entirely single translation unit, including libraries, and is still mostly parallel

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1 месяц назад

Pavel

Thomas
Molly Rocket (Casey) does single translation unit ...

Interesting, so it's a gigantic unity bucket then. Didn't think that would ever work

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1 месяц назад

Thomas

Pavel
Interesting, so it's a gigantic unity bucket then....

Well no, more like one unity per project I bet, and something like <10 projects

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1 месяц назад