Defining an Executable Package

Start a new Scarb project with scarb new <project_name>. In your Scarb.toml file:

1. Set the package to compile to a Cairo executable by adding [executable] (note that lib or starknet-contract targets cannot be executed in this way).
2. Add the cairo_execute=">=2.11.2" plugin to your dependencies.
3. Disable gas usage by adding enable-gas = false under the [cairo] section (gas is only supported for lib or starknet-contract targets).

Below we have an example of the manifest file of a simple executable

[package]
name = "test_execute"
version = "0.1.0"
edition = "{{ constants.edition }}"

[[target.executable]]

[cairo]
enable-gas = false

[dependencies]
cairo_execute = "{{ rel.stable.starknetPackageVersionReq }}"

Now we can move on to the code itself. An executable project must have exactly one function annotated with the #[executable] attribute. Consider the following simple lib.cairo file of an executable project:

#[executable]
fn main(num: u8) -> u8 {
    num
}

You can now run:

scarb execute -p test_execute --print-program-output --arguments 5

Where test_execute is the name of the package with the executable target (as defined in our Scarb.toml manifest).

The above command runs our executable function within the test-execute package and prints the program's output segment.

The execution information will be saved under the target/execute/<target name> directory. For each execution, a new output directory will be created, with consecutive number as names (e.g. execution1, execution2, ...). To clean the target directory, you can use the scarb clean command.

For more information see detailed scarb execute documentation.