sqlite3pp as header-only library

[jpetso]

The code is mostly forwarding to sqlite3 functions directly, and no build system is provided as sqlite3pp is meant to be included directly into the project tree (as far as I understand it). I think this makes it a perfect candidate for being a header-only library.

I would imagine it needs only a few changes:

• Declare all exportable symbols (probably just class methods) as inline.
• Rename .cpp files to .ipp and include them from the .h
• Put all of that into a folder include/sqlite3pp, so parent projects can add [sqlite3pp-repo]/include to their include directories.

[jpetso]

This would also reduce the need for something like PR #10 (although a similar CMake script to install the header files could make life easier for users not using git submodule).

[iwongu]

I'm not so sure about making this header-only. It has a benefit of easier installation but has some disadvantages too such as compilation time.
I still prefer having cpp files.

[jpetso]

Given the (fairly minimal) amount of code in sqlite3pp compared to existing system headers, and the number of files that you're actually likely to use it in, I don't believe compilation time to be much of an issue. (Much bigger libraries such as Boost or websocketpp do header-only on a routine basis and while Boost is not loved everywhere, compilation times are the least of complaints I hear/read about it.)

Header-only also has the advantage that no symbol clashes can occur. As an example, if I build sqlite3pp as part of my libsomething.a and also include it in libsomethingelse.a, I can't link both of them together into a single executable without first factoring out sqlite3pp into a separate library (which was what issue #10 wanted to do but you were not in favour of it). With a header-only library, no symbols are exported so I can link both of my libraries together without any further work.

However, I understand that this is your project so you have final say over its direction. Thank you for considering it :)

[koziez]

I would also love to see this feature

[rcmgleite]

+1

[iwongu]

fyi, I'm considering this change positively.

[sr1919]

+1

[iwongu]

Can some of you test this branch if you are interested in header only version of sqlite3pp?
https://github.com/iwongu/sqlite3pp/tree/headeronly/headeronly_src

[iwongu]

I merged it to master branch. I'm closing this issue. Please report bugs if you find any in header only version.

[jpetso]

Thanks! :D
I'll try it out and report back if something turns out not to work.

[jpetso]

Since you left a note on the README, I thought I'd comment to say that we're trying it and it seems to work here :)