RustPython
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/extra_tests/snippets/builtins_ctypes.py b/extra_tests/snippets/builtins_ctypes.py
@@ -0,0 +1,105 @@
+from _ctypes import sizeof
+from _ctypes import _SimpleCData
+from struct import calcsize as _calcsize
+
+def _check_size(typ, typecode=None):
+    # Check if sizeof(ctypes_type) against struct.calcsize.  This
+    # should protect somewhat against a misconfigured libffi.
+    from struct import calcsize
+    if typecode is None:
+        # Most _type_ codes are the same as used in struct
+        typecode = typ._type_
+    actual, required = sizeof(typ), calcsize(typecode)
+    if actual != required:
+        raise SystemError("sizeof(%s) wrong: %d instead of %d" % \
+                          (typ, actual, required))
+
+class c_short(_SimpleCData):
+    _type_ = "h"
+_check_size(c_short)
+
+class c_ushort(_SimpleCData):
+    _type_ = "H"
+_check_size(c_ushort)
+
+class c_long(_SimpleCData):
+    _type_ = "l"
+_check_size(c_long)
+
+class c_ulong(_SimpleCData):
+    _type_ = "L"
+_check_size(c_ulong)
+
+if _calcsize("i") == _calcsize("l"):
+    # if int and long have the same size, make c_int an alias for c_long
+    c_int = c_long
+    c_uint = c_ulong
+else:
+    class c_int(_SimpleCData):
+        _type_ = "i"
+    _check_size(c_int)
+
+    class c_uint(_SimpleCData):
+        _type_ = "I"
+    _check_size(c_uint)
+
+class c_float(_SimpleCData):
+    _type_ = "f"
+_check_size(c_float)
+
+class c_double(_SimpleCData):
+    _type_ = "d"
+_check_size(c_double)
+
+class c_longdouble(_SimpleCData):
+    _type_ = "g"
+if sizeof(c_longdouble) == sizeof(c_double):
+    c_longdouble = c_double
+
+if _calcsize("l") == _calcsize("q"):
+    # if long and long long have the same size, make c_longlong an alias for c_long
+    c_longlong = c_long
+    c_ulonglong = c_ulong
+else:
+    class c_longlong(_SimpleCData):
+        _type_ = "q"
+    _check_size(c_longlong)
+
+    class c_ulonglong(_SimpleCData):
+        _type_ = "Q"
+    ##    def from_param(cls, val):
+    ##        return ('d', float(val), val)
+    ##    from_param = classmethod(from_param)
+    _check_size(c_ulonglong)
+
+class c_ubyte(_SimpleCData):
+    _type_ = "B"
+c_ubyte.__ctype_le__ = c_ubyte.__ctype_be__ = c_ubyte
+# backward compatibility:
+##c_uchar = c_ubyte
+_check_size(c_ubyte)
+
+class c_byte(_SimpleCData):
+    _type_ = "b"
+c_byte.__ctype_le__ = c_byte.__ctype_be__ = c_byte
+_check_size(c_byte)
+
+class c_char(_SimpleCData):
+    _type_ = "c"
+c_char.__ctype_le__ = c_char.__ctype_be__ = c_char
+_check_size(c_char)
+
+class c_char_p(_SimpleCData):
+    _type_ = "z"
+    def __repr__(self):
+        return "%s(%s)" % (self.__class__.__name__, c_void_p.from_buffer(self).value)
+_check_size(c_char_p, "P")
+
+class c_void_p(_SimpleCData):
+    _type_ = "P"
+c_voidp = c_void_p # backwards compatibility (to a bug)
+_check_size(c_void_p)
+
+class c_bool(_SimpleCData):
+    _type_ = "?"
+_check_size(c_bool)
diff --git a/vm/Cargo.toml b/vm/Cargo.toml
@@ -99,14 +99,15 @@ uname = "0.1.1"
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 rustyline = { workspace = true }
 which = "6"
+errno = "0.3"
+widestring = { workspace = true }
 
 [target.'cfg(any(not(target_arch = "wasm32"), target_os = "wasi"))'.dependencies]
 num_cpus = "1.13.1"
 
 [target.'cfg(windows)'.dependencies]
 junction = { workspace = true }
 schannel = { workspace = true }
-widestring = { workspace = true }
 winreg = "0.52"
 
 [target.'cfg(windows)'.dependencies.windows]

diff --git a/vm/src/stdlib/ctypes.rs b/vm/src/stdlib/ctypes.rs
@@ -0,0 +1,107 @@
+pub(crate) mod base;
+
+use crate::builtins::PyModule;
+use crate::{PyRef, VirtualMachine};
+
+pub(crate) fn make_module(vm: &VirtualMachine) -> PyRef<PyModule> {
+    let module = _ctypes::make_module(vm);
+    base::extend_module_nodes(vm, &module);
+    module
+}
+
+#[pymodule]
+pub(crate) mod _ctypes {
+    use super::base::PyCSimple;
+    use crate::builtins::PyTypeRef;
+    use crate::class::StaticType;
+    use crate::function::Either;
+    use crate::{AsObject, PyObjectRef, PyResult, TryFromObject, VirtualMachine};
+    use crossbeam_utils::atomic::AtomicCell;
+    use std::ffi::{
+        c_double, c_float, c_int, c_long, c_longlong, c_schar, c_short, c_uchar, c_uint, c_ulong,
+        c_ulonglong,
+    };
+    use std::mem;
+    use widestring::WideChar;
+
+    pub fn get_size(ty: &str) -> usize {
+        match ty {
+            "u" => mem::size_of::<WideChar>(),
+            "c" | "b" => mem::size_of::<c_schar>(),
+            "h" => mem::size_of::<c_short>(),
+            "H" => mem::size_of::<c_short>(),
+            "i" => mem::size_of::<c_int>(),
+            "I" => mem::size_of::<c_uint>(),
+            "l" => mem::size_of::<c_long>(),
+            "q" => mem::size_of::<c_longlong>(),
+            "L" => mem::size_of::<c_ulong>(),
+            "Q" => mem::size_of::<c_ulonglong>(),
+            "f" => mem::size_of::<c_float>(),
+            "d" | "g" => mem::size_of::<c_double>(),
+            "?" | "B" => mem::size_of::<c_uchar>(),
+            "P" | "z" | "Z" => mem::size_of::<usize>(),
+            _ => unreachable!(),
+        }
+    }
+
+    const SIMPLE_TYPE_CHARS: &str = "cbBhHiIlLdfguzZPqQ?";
+
+    pub fn new_simple_type(
+        cls: Either<&PyObjectRef, &PyTypeRef>,
+        vm: &VirtualMachine,
+    ) -> PyResult<PyCSimple> {
+        let cls = match cls {
+            Either::A(obj) => obj,
+            Either::B(typ) => typ.as_object(),
+        };
+
+        if let Ok(_type_) = cls.get_attr("_type_", vm) {
+            if _type_.is_instance((&vm.ctx.types.str_type).as_ref(), vm)? {
+                let tp_str = _type_.str(vm)?.to_string();
+
+                if tp_str.len() != 1 {
+                    Err(vm.new_value_error(
+                        format!("class must define a '_type_' attribute which must be a string of length 1, str: {tp_str}"),
+                    ))
+                } else if !SIMPLE_TYPE_CHARS.contains(tp_str.as_str()) {
+                    Err(vm.new_attribute_error(format!("class must define a '_type_' attribute which must be\n a single character string containing one of {SIMPLE_TYPE_CHARS}, currently it is {tp_str}.")))
+                } else {
+                    Ok(PyCSimple {
+                        _type_: tp_str,
+                        _value: AtomicCell::new(vm.ctx.none()),
+                    })
+                }
+            } else {
+                Err(vm.new_type_error("class must define a '_type_' string attribute".to_string()))
+            }
+        } else {
+            Err(vm.new_attribute_error("class must define a '_type_' attribute".to_string()))
+        }
+    }
+
+    #[pyfunction(name = "sizeof")]
+    pub fn size_of(tp: Either<PyTypeRef, PyObjectRef>, vm: &VirtualMachine) -> PyResult<usize> {
+        match tp {
+            Either::A(type_) if type_.fast_issubclass(PyCSimple::static_type()) => {
+                let zelf = new_simple_type(Either::B(&type_), vm)?;
+                Ok(get_size(zelf._type_.as_str()))
+            }
+            Either::B(obj) if obj.has_attr("size_of_instances", vm)? => {
+                let size_of_method = obj.get_attr("size_of_instances", vm)?;
+                let size_of_return = size_of_method.call(vec![], vm)?;
+                Ok(usize::try_from_object(vm, size_of_return)?)
+            }
+            _ => Err(vm.new_type_error("this type has no size".to_string())),
+        }
+    }
+
+    #[pyfunction]
+    fn get_errno() -> i32 {
+        errno::errno().0
+    }
+
+    #[pyfunction]
+    fn set_errno(value: i32) {
+        errno::set_errno(errno::Errno(value));
+    }
+}