cl3

A Rust adapter for the Khronos OpenCL API.

Description

A functional, safe Rust interface to the Khronos OpenCL 3.0 C API based upon the opencl-sys OpenCL FFI bindings.
It is the foundation of the opencl3 crate which provides a simpler, object based model of the OpenCL 3.0 API.

OpenCL 3.0 is a unified specification that adds little new functionality to previous OpenCL versions.
It specifies that all OpenCL 1.2 features are mandatory, while all OpenCL 2.x and 3.0 features are now optional.

OpenCL also has extensions that enable other features such as OpenGL and Direct X interoperability, see OpenCL Extensions. This library includes FFI bindings to use OpenCL extensions.

Design

This crate applies the adapter pattern to convert OpenCL C API functions into Rust functions that return a Result containing the desired result of the C function or the OpenCL error code. The only exception is svm_free, which just provides a safe wrapper for the clSVMFree C API function.

Most of the modules are named after their equivalent "API" sections in cl.h. They contain Rust adapter functions for the OpenCL API C functions defined in those sections with their associated types and constants.
For more information see the Rust documentation.

Use

Ensure that an OpenCL Installable Client Driver (ICD) and the appropriate OpenCL hardware driver(s) are installed, see OpenCL Installation.

cl3 can support dynamic or static linking.

Dynamic Linking

dynamic linking is much simpler than static linking, so it is the default.

dynamic linking is enabled by adding the following to your project's Cargo.toml:

[dependencies]
cl3 = "0.11"

Static Linking

The static API for OpenCL versions and extensions are controlled by Rust features such as "CL_VERSION_2_0" or "cl_khr_gl_sharing". To enable an OpenCL version, the feature for static, the OpenCL version and all previous OpenCL versions must be enabled, e.g. for "CL_VERSION_2_0": "static", "CL_VERSION_1_1" and "CL_VERSION_1_2" must also be enabled.

Rust deprecation warnings are given for OpenCL API functions that are deprecated by an enabled OpenCL version e.g., clCreateCommandQueue is deprecated whenever "CL_VERSION_2_0" is enabled.

static linking requires the specified features to be present in the ICD loader. It is difficult to know in advance what features will be available. For example to statically link the features of an OpenCL 2.0 ICD loader add the following to your project's Cargo.toml:

[dependencies.cl3]
version = "0.11"
features = ["static", "CL_VERSION_1_1", "CL_VERSION_1_2", "CL_VERSION_2_0"]

OpenCL extensions

OpenCL extensions can also be enabled by adding their features, e.g.:

[dependencies.cl3]
version = "0.11"
features = ["static", "CL_VERSION_1_1", "CL_VERSION_1_2", "cl_khr_gl_sharing", "cl_khr_dx9_media_sharing"]

However, it is much simpler to enable OpenCL extensions by using the dynamic linking feature.

Tests

The crate contains unit, documentation and integration tests.
The tests run the platform and device info functions (among others) so they can provide useful information about OpenCL capabilities of the system.

It is recommended to run the tests in single-threaded mode, since some of them can interfere with each other when run multi-threaded, e.g.:

cargo test -- --test-threads=1 --show-output

The integration tests are marked ignore so use the following command to run them:

cargo test -- --test-threads=1 --show-output --ignored

Note: the tests run using the dynamic feature.

Examples

The tests provide examples of how the crate may be used, e.g. see: platform, device, context and integration_test.

Contribution

If you want to contribute through code or documentation, the Contributing guide is the best place to start. If you have any questions, please feel free to ask. Just please abide by our Code of Conduct.

License

Licensed under the Apache License, Version 2.0, as per Khronos Group OpenCL.
You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0

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 licensed as above, without any additional terms or conditions.

OpenCL and the OpenCL logo are trademarks of Apple Inc. used by permission by Khronos.