diff --git a/src/operator/bound.rs b/src/operator/bound.rs
index 58219c4..452736f 100644
--- a/src/operator/bound.rs
+++ b/src/operator/bound.rs
@@ -9,7 +9,7 @@ use super::{
 	kernel::{Kernel, KernelAttributes, KernelContext},
 	DummyOperator, Operator
 };
-use crate::error::IntoStatus;
+use crate::{error::IntoStatus, extern_system_fn};
 
 #[repr(C)] // <- important! a defined layout allows us to store extra data after the `OrtCustomOp` that we can retrieve later
 pub(crate) struct BoundOperator<O: Operator> {
@@ -65,115 +65,147 @@ impl<O: Operator> BoundOperator<O> {
 		&*op.cast()
 	}
 
-	pub(crate) unsafe extern "C" fn CreateKernelV2(
-		_: *const ort_sys::OrtCustomOp,
-		_: *const ort_sys::OrtApi,
-		info: *const ort_sys::OrtKernelInfo,
-		kernel_ptr: *mut *mut ort_sys::c_void
-	) -> *mut ort_sys::OrtStatus {
-		let kernel = match O::create_kernel(&KernelAttributes::new(info)) {
-			Ok(kernel) => kernel,
-			e => return e.into_status()
-		};
-		*kernel_ptr = (Box::leak(Box::new(kernel)) as *mut O::Kernel).cast();
-		Ok(()).into_status()
-	}
-
-	pub(crate) unsafe extern "C" fn ComputeKernelV2(kernel_ptr: *mut ort_sys::c_void, context: *mut ort_sys::OrtKernelContext) -> *mut ort_sys::OrtStatus {
-		let context = KernelContext::new(context);
-		O::Kernel::compute(unsafe { &mut *kernel_ptr.cast::<O::Kernel>() }, &context).into_status()
-	}
-
-	pub(crate) unsafe extern "C" fn KernelDestroy(op_kernel: *mut ort_sys::c_void) {
-		drop(Box::from_raw(op_kernel.cast::<O::Kernel>()));
-	}
-
-	pub(crate) unsafe extern "C" fn GetName(op: *const ort_sys::OrtCustomOp) -> *const ort_sys::c_char {
-		let safe = Self::safe(op);
-		safe.name.as_ptr()
-	}
-	pub(crate) unsafe extern "C" fn GetExecutionProviderType(op: *const ort_sys::OrtCustomOp) -> *const ort_sys::c_char {
-		let safe = Self::safe(op);
-		safe.execution_provider_type.as_ref().map(|c| c.as_ptr()).unwrap_or_else(ptr::null)
-	}
-
-	pub(crate) unsafe extern "C" fn GetStartVersion(_: *const ort_sys::OrtCustomOp) -> ort_sys::c_int {
-		O::min_version()
-	}
-	pub(crate) unsafe extern "C" fn GetEndVersion(_: *const ort_sys::OrtCustomOp) -> ort_sys::c_int {
-		O::max_version()
-	}
-
-	pub(crate) unsafe extern "C" fn GetInputMemoryType(_: *const ort_sys::OrtCustomOp, index: ort_sys::size_t) -> ort_sys::OrtMemType {
-		O::inputs()[index as usize].memory_type.into()
-	}
-	pub(crate) unsafe extern "C" fn GetInputCharacteristic(
-		_: *const ort_sys::OrtCustomOp,
-		index: ort_sys::size_t
-	) -> ort_sys::OrtCustomOpInputOutputCharacteristic {
-		O::inputs()[index as usize].characteristic.into()
-	}
-	pub(crate) unsafe extern "C" fn GetOutputCharacteristic(
-		_: *const ort_sys::OrtCustomOp,
-		index: ort_sys::size_t
-	) -> ort_sys::OrtCustomOpInputOutputCharacteristic {
-		O::outputs()[index as usize].characteristic.into()
-	}
-	pub(crate) unsafe extern "C" fn GetInputTypeCount(_: *const ort_sys::OrtCustomOp) -> ort_sys::size_t {
-		O::inputs().len() as _
-	}
-	pub(crate) unsafe extern "C" fn GetOutputTypeCount(_: *const ort_sys::OrtCustomOp) -> ort_sys::size_t {
-		O::outputs().len() as _
-	}
-	pub(crate) unsafe extern "C" fn GetInputType(_: *const ort_sys::OrtCustomOp, index: ort_sys::size_t) -> ort_sys::ONNXTensorElementDataType {
-		O::inputs()[index as usize]
-			.r#type
-			.map(|c| c.into())
-			.unwrap_or(ort_sys::ONNXTensorElementDataType::ONNX_TENSOR_ELEMENT_DATA_TYPE_UNDEFINED)
-	}
-	pub(crate) unsafe extern "C" fn GetOutputType(_: *const ort_sys::OrtCustomOp, index: ort_sys::size_t) -> ort_sys::ONNXTensorElementDataType {
-		O::outputs()[index as usize]
-			.r#type
-			.map(|c| c.into())
-			.unwrap_or(ort_sys::ONNXTensorElementDataType::ONNX_TENSOR_ELEMENT_DATA_TYPE_UNDEFINED)
-	}
-	pub(crate) unsafe extern "C" fn GetVariadicInputMinArity(_: *const ort_sys::OrtCustomOp) -> ort_sys::c_int {
-		O::inputs()
-			.into_iter()
-			.find(|c| c.characteristic == InputOutputCharacteristic::Variadic)
-			.and_then(|c| c.variadic_min_arity)
-			.unwrap_or(1)
-			.try_into()
-			.expect("input minimum arity overflows i32")
-	}
-	pub(crate) unsafe extern "C" fn GetVariadicInputHomogeneity(_: *const ort_sys::OrtCustomOp) -> ort_sys::c_int {
-		O::inputs()
-			.into_iter()
-			.find(|c| c.characteristic == InputOutputCharacteristic::Variadic)
-			.and_then(|c| c.variadic_homogeneity)
-			.unwrap_or(false)
-			.into()
-	}
-	pub(crate) unsafe extern "C" fn GetVariadicOutputMinArity(_: *const ort_sys::OrtCustomOp) -> ort_sys::c_int {
-		O::outputs()
-			.into_iter()
-			.find(|c| c.characteristic == InputOutputCharacteristic::Variadic)
-			.and_then(|c| c.variadic_min_arity)
-			.unwrap_or(1)
-			.try_into()
-			.expect("output minimum arity overflows i32")
-	}
-	pub(crate) unsafe extern "C" fn GetVariadicOutputHomogeneity(_: *const ort_sys::OrtCustomOp) -> ort_sys::c_int {
-		O::outputs()
-			.into_iter()
-			.find(|c| c.characteristic == InputOutputCharacteristic::Variadic)
-			.and_then(|c| c.variadic_homogeneity)
-			.unwrap_or(false)
-			.into()
-	}
-
-	pub(crate) unsafe extern "C" fn InferOutputShapeFn(_: *const ort_sys::OrtCustomOp, arg1: *mut ort_sys::OrtShapeInferContext) -> *mut ort_sys::OrtStatus {
-		O::get_infer_shape_function().expect("missing infer shape function")(arg1).into_status()
+	extern_system_fn! {
+		pub(crate) unsafe fn CreateKernelV2(
+			_: *const ort_sys::OrtCustomOp,
+			_: *const ort_sys::OrtApi,
+			info: *const ort_sys::OrtKernelInfo,
+			kernel_ptr: *mut *mut ort_sys::c_void
+		) -> *mut ort_sys::OrtStatus {
+			let kernel = match O::create_kernel(&KernelAttributes::new(info)) {
+				Ok(kernel) => kernel,
+				e => return e.into_status()
+			};
+			*kernel_ptr = (Box::leak(Box::new(kernel)) as *mut O::Kernel).cast();
+			Ok(()).into_status()
+		}
+	}
+
+	extern_system_fn! {
+		pub(crate) unsafe fn ComputeKernelV2(kernel_ptr: *mut ort_sys::c_void, context: *mut ort_sys::OrtKernelContext) -> *mut ort_sys::OrtStatus {
+			let context = KernelContext::new(context);
+			O::Kernel::compute(unsafe { &mut *kernel_ptr.cast::<O::Kernel>() }, &context).into_status()
+		}
+	}
+
+	extern_system_fn! {
+		pub(crate) unsafe fn KernelDestroy(op_kernel: *mut ort_sys::c_void) {
+			drop(Box::from_raw(op_kernel.cast::<O::Kernel>()));
+		}
+	}
+
+	extern_system_fn! {
+		pub(crate) unsafe fn GetName(op: *const ort_sys::OrtCustomOp) -> *const ort_sys::c_char {
+			let safe = Self::safe(op);
+			safe.name.as_ptr()
+		}
+	}
+	extern_system_fn! {
+		pub(crate) unsafe fn GetExecutionProviderType(op: *const ort_sys::OrtCustomOp) -> *const ort_sys::c_char {
+			let safe = Self::safe(op);
+			safe.execution_provider_type.as_ref().map(|c| c.as_ptr()).unwrap_or_else(ptr::null)
+		}
+	}
+
+	extern_system_fn! {
+		pub(crate) unsafe fn GetStartVersion(_: *const ort_sys::OrtCustomOp) -> ort_sys::c_int {
+			O::min_version()
+		}
+	}
+	extern_system_fn! {
+		pub(crate) unsafe fn GetEndVersion(_: *const ort_sys::OrtCustomOp) -> ort_sys::c_int {
+			O::max_version()
+		}
+	}
+
+	extern_system_fn! {
+		pub(crate) unsafe fn GetInputMemoryType(_: *const ort_sys::OrtCustomOp, index: ort_sys::size_t) -> ort_sys::OrtMemType {
+			O::inputs()[index as usize].memory_type.into()
+		}
+	}
+	extern_system_fn! {
+		pub(crate) unsafe fn GetInputCharacteristic(_: *const ort_sys::OrtCustomOp, index: ort_sys::size_t) -> ort_sys::OrtCustomOpInputOutputCharacteristic {
+			O::inputs()[index as usize].characteristic.into()
+		}
+	}
+	extern_system_fn! {
+		pub(crate) unsafe fn GetOutputCharacteristic(_: *const ort_sys::OrtCustomOp, index: ort_sys::size_t) -> ort_sys::OrtCustomOpInputOutputCharacteristic {
+			O::outputs()[index as usize].characteristic.into()
+		}
+	}
+	extern_system_fn! {
+		pub(crate) unsafe fn GetInputTypeCount(_: *const ort_sys::OrtCustomOp) -> ort_sys::size_t {
+			O::inputs().len() as _
+		}
+	}
+	extern_system_fn! {
+		pub(crate) unsafe fn GetOutputTypeCount(_: *const ort_sys::OrtCustomOp) -> ort_sys::size_t {
+			O::outputs().len() as _
+		}
+	}
+	extern_system_fn! {
+		pub(crate) unsafe fn GetInputType(_: *const ort_sys::OrtCustomOp, index: ort_sys::size_t) -> ort_sys::ONNXTensorElementDataType {
+			O::inputs()[index as usize]
+				.r#type
+				.map(|c| c.into())
+				.unwrap_or(ort_sys::ONNXTensorElementDataType::ONNX_TENSOR_ELEMENT_DATA_TYPE_UNDEFINED)
+		}
+	}
+	extern_system_fn! {
+		pub(crate) unsafe fn GetOutputType(_: *const ort_sys::OrtCustomOp, index: ort_sys::size_t) -> ort_sys::ONNXTensorElementDataType {
+			O::outputs()[index as usize]
+				.r#type
+				.map(|c| c.into())
+				.unwrap_or(ort_sys::ONNXTensorElementDataType::ONNX_TENSOR_ELEMENT_DATA_TYPE_UNDEFINED)
+		}
+	}
+	extern_system_fn! {
+		pub(crate) unsafe fn GetVariadicInputMinArity(_: *const ort_sys::OrtCustomOp) -> ort_sys::c_int {
+			O::inputs()
+				.into_iter()
+				.find(|c| c.characteristic == InputOutputCharacteristic::Variadic)
+				.and_then(|c| c.variadic_min_arity)
+				.unwrap_or(1)
+				.try_into()
+				.expect("input minimum arity overflows i32")
+		}
+	}
+	extern_system_fn! {
+		pub(crate) unsafe fn GetVariadicInputHomogeneity(_: *const ort_sys::OrtCustomOp) -> ort_sys::c_int {
+			O::inputs()
+				.into_iter()
+				.find(|c| c.characteristic == InputOutputCharacteristic::Variadic)
+				.and_then(|c| c.variadic_homogeneity)
+				.unwrap_or(false)
+				.into()
+		}
+	}
+	extern_system_fn! {
+		pub(crate) unsafe fn GetVariadicOutputMinArity(_: *const ort_sys::OrtCustomOp) -> ort_sys::c_int {
+			O::outputs()
+				.into_iter()
+				.find(|c| c.characteristic == InputOutputCharacteristic::Variadic)
+				.and_then(|c| c.variadic_min_arity)
+				.unwrap_or(1)
+				.try_into()
+				.expect("output minimum arity overflows i32")
+		}
+	}
+	extern_system_fn! {
+		pub(crate) unsafe fn GetVariadicOutputHomogeneity(_: *const ort_sys::OrtCustomOp) -> ort_sys::c_int {
+			O::outputs()
+				.into_iter()
+				.find(|c| c.characteristic == InputOutputCharacteristic::Variadic)
+				.and_then(|c| c.variadic_homogeneity)
+				.unwrap_or(false)
+				.into()
+		}
+	}
+
+	extern_system_fn! {
+		pub(crate) unsafe fn InferOutputShapeFn(_: *const ort_sys::OrtCustomOp, arg1: *mut ort_sys::OrtShapeInferContext) -> *mut ort_sys::OrtStatus {
+			O::get_infer_shape_function().expect("missing infer shape function")(arg1).into_status()
+		}
 	}
 }