Function require_module 

pub fn require_module(
    table: &mut modulestab,
    modname: &str,
    features: Option<&[String]>,
    silent: i32,
    feat_pat: bool,
) -> i32

Port of require_module() from Src/module.c:2344. — C decl require_module(const char *module, Feature_enables features, int silent).

C body c:2342-2360:

mod_export int
require_module(const char *module, Feature_enables features, int silent)
{
    Module m = NULL;
    int ret = 0;
    queue_signals();
    m = find_module(module, FINDMOD_ALIASP, &module);
    if (!m || !m->u.handle ||
        (m->node.flags & MOD_UNLOAD))
        ret = load_module(module, features, silent);
    else
        ret = do_module_features(m, features, 0);
    unqueue_signals();
    return ret;
}

Two branches: when the module isn’t loaded yet (or is mid-unload), route through load_module which runs the full setup → features → boot lifecycle. When it’s already loaded, skip to do_module_features to just enable the requested per-feature surface — much cheaper.

Static-link analog of m->u.handle is MOD_INIT_B (boot ran): once boot_module has fired, the module is “loaded” in zshrs’s non-dlopen world. WARNING: param names don’t match C — Rust=(table, modname, features, silent) vs C=(module, features, silent)