Environment

std.env contains the small process-environment helpers used by command-line programs. The current surface is deliberately narrow: borrowed argument access and borrowed environment lookup.

Current-directory access, environment mutation, environment iteration, subprocess management, and high-level exit helpers are not part of this module. Use std.os for low-level process exits.

import std.env;
import std.io;

fn main() {
    let args = env.args();

    io.println("argc={args.length}");
    if args.length > 1 {
        io.println("first={args[1]}");
    }
}

args() -> const [str] returns the process argument slice for the current program. args[0] is the executable path or name supplied by the host runtime, and later elements are user arguments.

The returned slice is borrowed process-startup storage. Programs must not store it in longer-lived owners or mutate it. It remains valid for the duration of the process.

import std.env;
import std.io;

fn main() {
    let home = env.get("HOME");
    if home == null {
        io.eprintln("HOME is not set");
        return;
    }

    io.println("HOME={home}");
}

get(name: str) -> str? returns the process environment value for name, or null when the variable is absent. The returned string is borrowed host environment storage. Zynx does not expose environment mutation here, so the borrow is stable for normal Zynx code until process exit.

Environment text is treated as process text and should be valid UTF-8 for portable Zynx programs. Byte-oriented environment handling is outside this checked text API.

Symbol	Signature	Notes
args	args() -> const [str]	Returns borrowed process arguments.
get	get(name: str) -> str?	Returns a borrowed environment value, or null when missing.