std/mem

std/mem exposes raw C allocation functions:

pub ext fun malloc(size: Int) *Void;
pub ext fun calloc(count: Int, size: Int) *Void;
pub ext fun realloc(pointer: *Void, size: Int) *Void;
pub ext fun free(pointer: *Void) Void;

These calls and all pointer access belong in an unsafe scope:

import "std/mem" as mem;

fun main() Int {
    unsafe {
        var raw = mem.malloc(sizeof(Int));
        if raw == null { return 1; }

        var value = raw as *Int;
        *value = 42;
        var result = *value;

        mem.free(raw);
        return result;
    }
}

Zap does not track the lifetime or size of memory returned here. Check for null, stay within the allocation, and release each successful allocation exactly once. Prefer managed Zap values outside FFI and low-level runtime code.

See Unsafe code for pointer rules and C interop for foreign declarations.