bool

A boolean. Not much else to say here.

Booleans are not actually stored inside the zval. Instead, they are treated as two different union types (the zval can be in a true or false state). An equivalent structure in Rust would look like:

enum Zval {
    True,
    False,
    String(&mut ZendString),
    Long(i64),
    // ...
}

Rust example

#![cfg_attr(windows, feature(abi_vectorcall))]
extern crate ext_php_rs;
use ext_php_rs::prelude::*;
#[php_function]
pub fn test_bool(input: bool) -> String {
    if input {
        "Yes!".into()
    } else {
        "No!".into()
    }
}
fn main() {}

PHP example

<?php

var_dump(test_bool(true)); // string(4) "Yes!"
var_dump(test_bool(false)); // string(3) "No!"

Rust example, taking by reference

#![cfg_attr(windows, feature(abi_vectorcall))]
extern crate ext_php_rs;
use ext_php_rs::prelude::*;
use ext_php_rs::types;
#[php_function]
pub fn test_bool(input: &mut types::Zval) {
    input.reference_mut().unwrap().set_bool(false);
}
fn main() {}