My single header libraries for C/C++.
|json.h||1.00||parser||848||zlib||non-allocating json parser|
|sched.h||1.00||multithreading||699||zlib||multithreaded task scheduler|
|sdefl.h||1.00||compression||525||public domain||deflate compressor|
|sinfl.h||1.00||decompression||320||public domain||deflate decompressor|
Total libraries: 5
Total lines of C code: 4487
Windows doesn't have standard directories where libraries live. That makes deploying libraries in Windows a lot more painful than open source developers on Unix-derivates generally realize. (It also makes library dependencies a lot worse in Windows.)
There's also a common problem in Windows where a library was built against a different version of the runtime library, which causes link conflicts and confusion. Shipping the libs as headers means you normally just compile them straight into your project without making libraries, thus sidestepping that problem.
Making them a single file makes it very easy to just drop them into a project that needs them. (Of course you can still put them in a proper shared library tree if you want.)
Why not two files, one a header and one an implementation? The difference between 10 files and 9 files is not a big deal, but the difference between 2 files and 1 file is a big deal. You don't need to zip or tar the files up, you don't have to remember to attach two files, etc.
Each file has documentation, basic ussage description and examples at the top of the file. In addition each API function, struct and member variables are documented as well. Finally each library has a corresponding test file inside the test directory for additional working examples.
Personally I primarily use C instead of C++ and since I want to support both C and C++ and C++ is not useable from C I therefore focus on C.
I use C89 instead of C99/C11 for its portability between different compilers and accessiblity for other languages.