Hello, World

The smallest Cinder program prints a line and returns the exit code 0.

use "std/io.cnd";

fn main() -> i32 {
    println("Hello, world!");
    return 0;
}

$ ./cinder build hello.cnd --emit=bin -o hello
$ ./hello
Hello, world!

How it works

• use "std/io.cnd"; imports the standard I/O module.
• fn main() -> i32 is the entry point. i32 is the return type.
• println(s) writes a string and a newline to stdout.
• return 0; is the process exit code. 0 means success.

Exit codes

The return value of main becomes the exit code of the program.

// docs: check
fn main() -> i32 {
    return 3;
}

$ ./cinder build exit.cnd --emit=bin -o exit
$ ./exit
$ echo $?
3

Without a return value

main may also be a void function. The exit code is then 0.

use "std/io.cnd";

fn main() {
    println("done");
}

$ ./hello
done

cinder is the command-line wrapper. ./cinder check file.cnd runs only the compiler checks; ./cinder build produces a binary.