libostd/README.md

# octastd

**Work in progress, not ready for production use.**

OctaSTD is an extension of the C++17 standard library which mainly provides
ranges (to replace iterators) but also various other utilities like proper
streams, string formatting, coroutines, concurrency utilities and others. It's
meant to replace the more poorly designed parts of the C++ standard library to
make the language easier and more convenient to use.

It is not feature complete right now, as most things are still being worked on.

Documentation (currently outdated and incomplete) for OctaSTD can be found at
https://wiki.octaforge.org/docs/octastd.

## Supported compilers

Compiler | Version
-------- | -------
gcc/g++  | 7+
clang    | 4+

You need those mainly to get the right standard library version (libstdc++
or libc++). Other compilers might work as well, as long as the necessary
standard library features are supplied.

MSVC++ is unsupported and for the time being will remain unsupported. As of MS
Visual Studio 2017 RC, basic C++11 features are still broken and prevent usage
of the library, with no reasonable workarounds. I will be testing new versions
as they get released and mark it supported as soon as it actually works, but no
active effort will be put towards making it work. On Windows, you're free to
use GCC/Clang, if you need Visual Studio, LLVM integration exists.

## Why is C++17 necessary?

Sadly, it's not possible to properly integrate `std::string` and `std::hash`
with OctaSTD ranges without utilizing `std::string_view`. Also, C++17 provides
library features that OctaSTD would have to implement otherwise, which would
lead to potentially incompatible APIs. C++17 also provides some nice language
features (such as `if constexpr` and fold expressions) which allow a lot of
code to be written in a cleaner way. However, it is made sure that no features
beyond the minimum supported compiler are necessary to use the library.

## Supported operating systems and architectures

OctaSTD targets POSIX compliant operating systems and Windows. Features are
written with those in mind, and other targets are currently not supported.

The primary targets (regularly tested) are Linux, FreeBSD and Windows on x86
and x86\_64 as well as macOS on x86\_64. Secondary targets (irregularly tested)
are Linux and FreeBSD on ARM, AArch64 as well as macOS on x86. Tertiary targets
(rarely tested or untested but probably working and accepting patches for) are
other BSDs, Solaris and AIX on x86, x86\_64, ARM, AArch64, MIPS32 and PPC32/64
as well as other previously mentioned systems on architectures not included
in their Tier 1 or 2 support. Other targets are unsupported (might or might
not work, depending on POSIX compliance and ABI).

### Coroutines

Coroutines use platform specific assembly code taken from Boost.Context. There
is assembly for all of the targets mentioned above.

There is also support for stack allocators inspired again by the Boost.Context
library, with fixed size protected and unprotected allocators available on all
platforms, as well as a stack pool which allocates stacks in batches and
recycles dead stacks.

Compile with the `OSTD_USE_VALGRIND` macro defined if you want useful Valgrind
output when using coroutines - this makes Valgrind aware of the custom stacks.