build_native 0.0.4

Compile native extensions with package:build and CMake.

build_native

Compile native extensions with package:build, via CMake.

This is a 2-step build process:

1. Build *.{c,cc,cpp} files to .o.
2. Link files into a shared library.

Ultimately, to build everything, you will just need to run pub run build_runner build --output=build/vm.

The goal of this package is to use existing infrastructure to build native extensions.

Note that at the time of this writing, it is NECESSARY to provide an --output argument to the build_runner command; otherwise, native extensions cannot be resolved to their correct paths.

As an added note, Windows building is not supported YET.

As yet another note, this has not been tested on Linux, but it is developed on Mac, and the two platforms compile extensions almost exactly the same way.

Usage

build_native requires only very little configuration. However, this means that it can only serve one purpose: invoking the compiler on the user's system.

Source Files

Also, because of the nature of package:build, each input can only create one output. For *.c, *.cc, and *.cpp, files, the system compiler is invoked to create a .o file. To override this, set the CC environment variable when compiling C, or the CXX environment variable when compiling C++.

Files named *.macos.{c,cc,cpp} will only build on Mac. The same applies to linux and windows. This can be used to apply platform-specific settings in your build.

Master Build File

To perform linking, include an lib<extension_name>.build_native.yaml file in the directory where the extension should be built.

It should contain a list of source files to link together.

Note that these should all be asset ID's.

The simplest example, libsample_extension.build_native.yaml:

sources:
  - example|src/sample_extension.cc

See example/ for more.

All supported options:

flags:
  - "-O2"
sources:
  - example|sample_extension.cc
  - example|sample_extension.macos.cc # Will only be included on MacOS; ignored elsewhere
link:
  - example|some_lib.o
define:
  foo: bar
  DEBUG:

Platform-Specific Options

To specify options that should only apply to a given platform, add a <extension_name>.<platform_name>.macos.build_native.yaml file, for example, foo_bar.macos.build_native.yaml. This will be merged into the main options.

Platforms available: macos, windows, linux.

By providing this as the PLATFORM environment variable, you can override this.

Windows

Save yourself a hassle by running the build within the Visual Studio Developer Command Prompt.

Regardless, executables like cl.exe and link.exe should be available. Otherwise:

To enable a 64-bit toolset: https://docs.microsoft.com/en-us/cpp/build/how-to-enable-a-64-bit-visual-cpp-toolset-on-the-command-line

vcvarsall might be contained in: C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Auxiliary\Build

Unix

On Unix, if you some error like this:

fatal error: bits/c++config.h: No such file or directory

Then run:

sudo apt-get install -y gcc-multilib g++-multilib