'Hello, world!' in Chapel

Chapel is a programming language for productive parallel computing. This repository is a simple starting point for Chapel in GitHub Codespaces, with runnable examples in examples/.

Not in a Codespace yet? See Using a Codespace below to get started.

⚠️ Warning: Codespaces runs in a virtualized environment with shared hardware and a modest core count. Performance and available parallelism in Codespaces are not representative of what you should expect on a native Chapel installation.

Compile And Run With The Run Button In Codespaces VS Code

1. Open hello.chpl.
2. Wait for the Chapel extension and language tools to finish loading in Codespaces.
3. Click the Run button in the editor (top right) once to compile the code, and once more to run the current file.

Note: The Run button does not support multi-locale (distributed) programs. Use the terminal for those.

If the Run button does not appear right away, wait a bit longer and reopen the .chpl file.

Compile And Run In The Terminal

Compile and run the main hello-world program:

chpl hello.chpl
./hello

Compile and run one of the included examples:

chpl examples/hello3-datapar.chpl
./hello3-datapar

Simulated Distributed (Multi-Locale) Runs

The Codespace defaults to single-locale mode (CHPL_COMM=none).

To simulate multi-locale execution, compile with CHPL_COMM=gasnet:

CHPL_COMM=gasnet chpl examples/hello4-datapar-dist.chpl
./hello4-datapar-dist -nl 2

To avoid having to include CHPL_COMM in each compilation command, you can export it (you need to do this once per shell session). After this, you can compile as usual:

export CHPL_COMM=gasnet
chpl examples/hello4-datapar-dist.chpl
./hello4-datapar-dist -nl 2

Learn More And Try More Programs

To explore more language features or play further, you can copy in examples from Chapel Primers or a prior tutorial. The following links are also helpful:

• Learning Chapel
• Chapel Primers
• Chapel tutorial examples
• Multilocale Chapel Execution
• Download Chapel

Using a Codespace

This repository includes a devcontainer.json file, making it usable from GitHub Codespaces. When viewing this repository from GitHub's UI, click Use this template > Open in a codespace to get started. Or use the direct link: https://codespaces.new/chapel-lang/chapel-hello-world

The codespace includes the Visual Studio Code extension for Chapel, and tools such as chpl-language-server and chplcheck.