sys — process control

Source: std/sys.mw. Imports io.mw.

Foreign bindings

Function	Binds to (C)
exit(code: i32)	exit
c_system(command: *u8) -> i32	system

exit is exposed directly under its C name — there’s no Marrow-native wrapper, since the raw exit(3) signature is already exactly what you want.

Functions

exec(command: *u8) -> i32

Runs a shell command via system(3) and returns its exit status. Blocks until the command finishes, exactly like C’s system() (including running through /bin/sh -c on Unix-like systems).

panic(message: *u8)

Prints [FATAL PANIC] <message> to stderr and immediately terminates the process with exit(1). This function never returns — control flow does not continue past a panic() call, even though the compiler doesn’t currently model “never-returning” functions specially (the process is simply gone by the time execution would resume).

assert(condition: i8, message: *u8)

If condition is 0 (falsy), calls panic(message); otherwise does nothing. This is the standard library’s only assertion mechanism — there’s no built-in assert keyword or macro, just this plain function.

Example

@import("sys.mw")

fn divide(a: i64, b: i64) -> i64 {
    assert(cast(i8) (b != 0), "division by zero");
    ret a / b;
}

fn main(argc: i32, argv: rawptr) -> i32 {
    if (argc < 2) {
        panic("usage: prog <arg>");
    }
    ret exec("echo running");
};