SYS-BUILD

An experimental abstraction over the components required for building rust *-sys crates with FFI bindings.

See rust-embedded#481 for background discussion and #1 for a meta-issue.

Goals

To simplify the construction of *-sys crates that adequately support multiple target architectures, minimising the burden on crate authors to create and manage complex build.rs configurations and improving the crate consumer experience by providing consistent support for a set of required features.

Requirements

• Minimise surprise by providing working defaults for common configurations
  • Attempt to use non-interactive discovery mechanisms, provide useful errors, support overrides as required
• Support per-target configuration to pass to underlying build systems
  • ie. existing autotools may expect a variety of configuration options per-target
• Support both linking against system libraries and compiling and linking against static or dynamic libraries
• Support cross-platform use
  • packages should both work and be cross compilable using at least linux / windows / macos
• Provide cargo-centric mechanisms for configuration (no environmental variables required _by default)
• Support fetching pre-compiled libraries / headers for platforms where this is requried / useful
• Support testing of *-sys crates across supported hosts and targets

Status

No more than a rough idea. Check out the issues or add your own!

Usage

sys-build provides a high-level configuration that allows crate authors to declare how a library should be located, compiled, and linked in their build.rs, along with a set of features that can be re-exported from *-sys crates to allow higher level crates to choose which of the available mechanisms to use.

Features

• Locating Sources
  • source_dir enables building from an included directory / submodule
  • source_git enables building from a specified git repository
• Locating Libraries
  • use_pkgconfig enables system library discovery using pkgconfig
  • use_vcpkg enable system library discovery
  • lib_dir use default (or provided) library directory
  • lib_dl use a downloaded pre-compiled library
• Binding Generation
  • bindgen enables compile-time binding generation (otherwise included bindings are used)
• Linking mechanisms
  • link_static attempts to statically link the library
  • link_dymanic attempts to dynamically link the libary
• Compilation
  • cc enables compile-time library compilation via the cc crate (must be paired with source_dir or source_git)
  • make enables compile-time library compilation via make
  • cmake enables compile-time library compilation via cmake
  • autotools enables compile-time library compilation via autotools