cheapalloc

A simple crate to provide a GlobalAllocator that uses libc malloc & free, thus using an existing C heap. (thus the name: "C heap alloc")

The intended use is to enable heap-dependent features in Rust, e.g. Box, alloc::vec::Vec, alloc::string::String, etc when using Rust libraries via FFI from C, such that they can use the existing C heap.

The original mission of this crate was to enable use of Rust to make staticlibs for embedded applications on microcontrollers.

Dependencies

Requires nightly compiler due to the use of #![feature(lang_items)].

Using this Crate

Add the crate as a dependency, and the global allocator should be provided.
You will need to amend your linking system to

TODO: Linker instructions, e.g. --print-sysroot, -Wl,-lc, etc

NOTE: This crate can optionally define a out-of-memory panic_halt / oom handler via the provide_oom feature. This is currently implemented specifically for the Cortex-M architecture, with the idea that it alleviates the user/library from needing to include this block themselves.

Example

TODO: Include an example, or provide one in a separate github repo. Seriously powerful stuff like serde can be made to work on Cortex-M micros!

Pitfalls

Beyond the scope of this crate, but: linking a rust staticlib with an existing C program does present some issues due to the use of compiler-builtins by rust.

Some discussion here.

License

This template is licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)

• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.