#[php_extern] Attribute

Attribute used to annotate extern blocks which are deemed as PHP functions.

This allows you to 'import' PHP functions into Rust so that they can be called like regular Rust functions. Parameters can be any type that implements IntoZval, and the return type can be anything that implements [From<Zval>] (notice how Zval is consumed rather than borrowed in this case).

Unlike most other attributes, this does not need to be placed inside a #[php_module] block.

Panics

The function can panic when called under a few circumstances:

• The function could not be found or was not callable.
• One of the parameters could not be converted into a Zval.
• The actual function call failed internally.
• The output Zval could not be parsed into the output type.

The last point can be important when interacting with functions that return unions, such as strpos which can return an integer or a boolean. In this case, a Zval should be returned as parsing a boolean to an integer is invalid, and vice versa.

Example

This extern block imports the strpos function from PHP. Notice that the string parameters can take either [String] or [&str], the optional parameter offset is an [Option<i64>], and the return value is a Zval as the return type is an integer-boolean union.

#![cfg_attr(windows, feature(abi_vectorcall))]
extern crate ext_php_rs;
use ext_php_rs::{
    prelude::*,
    types::Zval,
};

#[php_extern]
extern "C" {
    fn strpos(haystack: &str, needle: &str, offset: Option<i64>) -> Zval;
}

#[php_function]
pub fn my_strpos() {
    assert_eq!(unsafe { strpos("Hello", "e", None) }.long(), Some(1));
}

#[php_module]
pub fn module(module: ModuleBuilder) -> ModuleBuilder {
    module.function(wrap_function!(my_strpos))
}
fn main() {}