pub unsafe trait AsPyPointer {
// Required method
fn as_ptr(&self) -> *mut PyObject;
}Expand description
Returns a borrowed pointer to a Python object.
The returned pointer will be valid for as long as self is. It may be null depending on the
implementation.
§Examples
use pyo3::prelude::*;
use pyo3::types::PyString;
use pyo3::ffi;
Python::with_gil(|py| {
let s: Py<PyString> = "foo".into_py(py);
let ptr = s.as_ptr();
let is_really_a_pystring = unsafe { ffi::PyUnicode_CheckExact(ptr) };
assert_eq!(is_really_a_pystring, 1);
});§Safety
For callers, it is your responsibility to make sure that the underlying Python object is not dropped too early. For example, the following code will cause undefined behavior:
Python::with_gil(|py| {
let ptr: *mut ffi::PyObject = 0xabad1dea_u32.into_py(py).as_ptr();
let isnt_a_pystring = unsafe {
// `ptr` is dangling, this is UB
ffi::PyUnicode_CheckExact(ptr)
};
});This happens because the pointer returned by as_ptr does not carry any lifetime information
and the Python object is dropped immediately after the 0xabad1dea_u32.into_py(py).as_ptr()
expression is evaluated. To fix the problem, bind Python object to a local variable like earlier
to keep the Python object alive until the end of its scope.
Implementors must ensure this returns a valid pointer to a Python object, which borrows a reference count from &self.
Required Methods§
Implementations on Foreign Types§
Source§impl<T> AsPyPointer for Option<T>where
T: AsPyPointer,
Convert None into a null pointer.
impl<T> AsPyPointer for Option<T>where
T: AsPyPointer,
Convert None into a null pointer.