C++ libraries and what inline has to do with them

[@CodeForYourself]

This lecture goes slightly in-depth in places. Don't worry! You won't have to do any of this manually! We will be using some build system like CMake or bazel for this. But to understand how those work it helps immensely to know what happens under the hood. 😜 Are you sold on this notion?

[@reubenthomas1033]

Yes absolutely!! I’ve never understood what Cmake is actually doing. I often get stuck during build errors. I would love to understand what actually goes on under the hood

[@ilarioantonioazzollini66]

I completely agree, thanks for the lecture! It would be very helpful imo if you could do an entire lecture dedicated to CMake and more in general on how to structure a project (probably there is no general way then some different examples of architectures would be required). Do you plan on doing something like that?

[@CodeForYourself]

Yep, that's the plan for the next (or one after that) video 😉

[@ilarioantonioazzollini66]

@@CodeForYourself Awesome, thank you again!

[@jonathans3021]

This lecture cleared up a lot of confusions I had about libraries, thank you!

[@CodeForYourself]

Glad to hear that!

[@ramcharanthota1016]

great lecture.Finally, I understadn ODR and inline really well

[@CodeForYourself]

Glad to hear it! 🙏

[@gabrielalmeidasantosdeoliv1870]

Excelent lecture, can see it took a lot of work too do.

[@CodeForYourself]

Yeah, I tried my best to be concise but still explain most of the stuff I wanted to explain. It's still not perfect, but I can always come back to it in the future and make it better 😉

[@ChrisOffner]

Another great lecture, thank you! :)

[@joy7673]

Hi, waiting for the following lectures.

[@CodeForYourself]

They're coming but probably towards 15th of November or so. I'm out for a conference and it's hard to squeeze everything together.

[@marwanzaghloul6065]

@@CodeForYourself take your time its going to be amazing lecture as usual , i cant wait 😅

[@muhammedkocaer8373]

I wanna ask you about #pragma. Do they not prevent multiple definitions of the same header? If it is, why it didn't prevent when linking? I know libfoo and libbar are different libraries so we have multiple copies. But when linking with the main code, why we couldnt rerun #pragma 😄? Why #pragma doesnt make inline's job also. I couldnt understand this.

[@CodeForYourself]

@@muhammedkocaer8373 thanks for the question! These are all confusing things. Let’s try to break them down. The pragma once is a preprocessor directive that can be seen by a # in front of it. This means that the compiler never sees it. Instead the preprocessor replaces it with some unique guard for this file so that when this file is included twice, it actually only gets included once. The include is also a preprocessor directive, so the compiler does not see it either. Instead, the preprocessor just textually replaces an include with the content of the underlying file. But only once because of the pragma once. Does this somewhat answer your question?

[@muhammedkocaer8373]

​@@CodeForYourself Now I get it. I asked this question as if it were performing a function task. But I forgot that it was a preprocessor. Thanks.

[@CodeForYourself]

@@muhammedkocaer8373 awesome! Glad I could help!

[@ChimiChanga1337]

What if we make header-only libraries instead.

[@CodeForYourself]

You mean like not ever use any other libraries?

[@ChimiChanga1337]

​@@CodeForYourself okay I'm too much of a beginner. I think I understand the tradeoffs of different types of libraries. Header only libs makes the devs life simple. But if you want to hide the implementation then they wont work.

[@CodeForYourself]

@@ChimiChanga1337 yes, you are exactly right! Also, header only libraries, when we have many of them, make compilation waaay too slow. With compiler libraries we are able to often compile them once and link all over the place. Does this make sense?

[@ChimiChanga1337]

@@CodeForYourself Yes, I understand now. I really want to thank you again for this course!

[@CodeForYourself]

@@ChimiChanga1337 my pleasure and I'm really happy that you like it! 🙏