Add Handle::is_null()

Changelog.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- Added `Handle::is_null()` to allow checking if a handle is a `NULL` value (#694)
 - Update Vulkan-Headers to 1.3.246 (#697, #723)
 - Added `VK_KHR_performance_query` device extension (#726)
 - Added `VK_EXT_shader_object` device extension (#732)

ash/src/vk.rs

@@ -49,4 +49,16 @@ pub trait Handle {
     const TYPE: ObjectType;
     fn as_raw(self) -> u64;
     fn from_raw(_: u64) -> Self;
+
+    /// Returns whether the handle is a `NULL` value.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # use ash::vk::{Handle, Instance};
+    ///
+    /// let instance = Instance::null();
+    /// assert!(instance.is_null());
+    /// ```
+    fn is_null(self) -> bool;
 }

ash/src/vk/macros.rs

@@ -99,6 +99,9 @@ macro_rules! handle_nondispatchable {
             fn from_raw(x: u64) -> Self {
                 Self(x)
             }
+            fn is_null(self) -> bool {
+                self.0 == 0
+            }
         }
         impl $name {
             pub const fn null() -> Self {
@@ -140,6 +143,9 @@ macro_rules! define_handle {
             fn from_raw(x: u64) -> Self {
                 Self(x as _)
             }
+            fn is_null(self) -> bool {
+                self.0.is_null()
+            }
         }
         unsafe impl Send for $name {}
         unsafe impl Sync for $name {}