diff --git a/examples/graphics_context.zig b/examples/graphics_context.zig
index df6367d..2026978 100644
--- a/examples/graphics_context.zig
+++ b/examples/graphics_context.zig
@@ -109,10 +109,7 @@ pub const GraphicsContext = struct {
         };
 
         self.instance = try self.vkb.createInstance(&.{
-            .flags = .{},
             .p_application_info = &app_info,
-            .enabled_layer_count = 0,
-            .pp_enabled_layer_names = undefined,
             .enabled_extension_count = glfw_exts_count,
             .pp_enabled_extension_names = @ptrCast([*]const [*:0]const u8, glfw_exts),
         }, null);
@@ -192,13 +189,11 @@ fn initializeCandidate(vki: InstanceDispatch, candidate: DeviceCandidate) !vk.De
     const priority = [_]f32{1};
     const qci = [_]vk.DeviceQueueCreateInfo{
         .{
-            .flags = .{},
             .queue_family_index = candidate.queues.graphics_family,
             .queue_count = 1,
             .p_queue_priorities = &priority,
         },
         .{
-            .flags = .{},
             .queue_family_index = candidate.queues.present_family,
             .queue_count = 1,
             .p_queue_priorities = &priority,
@@ -211,14 +206,10 @@ fn initializeCandidate(vki: InstanceDispatch, candidate: DeviceCandidate) !vk.De
         2;
 
     return try vki.createDevice(candidate.pdev, &.{
-        .flags = .{},
         .queue_create_info_count = queue_count,
         .p_queue_create_infos = &qci,
-        .enabled_layer_count = 0,
-        .pp_enabled_layer_names = undefined,
         .enabled_extension_count = required_device_extensions.len,
         .pp_enabled_extension_names = @ptrCast([*]const [*:0]const u8, &required_device_extensions),
-        .p_enabled_features = null,
     }, null);
 }
 
diff --git a/examples/swapchain.zig b/examples/swapchain.zig
index 2646a8d..70e437d 100644
--- a/examples/swapchain.zig
+++ b/examples/swapchain.zig
@@ -47,7 +47,6 @@ pub const Swapchain = struct {
             .exclusive;
 
         const handle = try gc.vkd.createSwapchainKHR(gc.dev, &.{
-            .flags = .{},
             .surface = gc.surface,
             .min_image_count = image_count,
             .image_format = surface_format.format,
@@ -77,7 +76,7 @@ pub const Swapchain = struct {
             allocator.free(swap_images);
         }
 
-        var next_image_acquired = try gc.vkd.createSemaphore(gc.dev, &.{ .flags = .{} }, null);
+        var next_image_acquired = try gc.vkd.createSemaphore(gc.dev, &.{}, null);
         errdefer gc.vkd.destroySemaphore(gc.dev, next_image_acquired, null);
 
         const result = try gc.vkd.acquireNextImageKHR(gc.dev, handle, std.math.maxInt(u64), next_image_acquired, .null_handle);
@@ -172,7 +171,6 @@ pub const Swapchain = struct {
             .swapchain_count = 1,
             .p_swapchains = @ptrCast([*]const vk.SwapchainKHR, &self.handle),
             .p_image_indices = @ptrCast([*]const u32, &self.image_index),
-            .p_results = null,
         });
 
         // Step 4: Acquire next frame
@@ -204,7 +202,6 @@ const SwapImage = struct {
 
     fn init(gc: *const GraphicsContext, image: vk.Image, format: vk.Format) !SwapImage {
         const view = try gc.vkd.createImageView(gc.dev, &.{
-            .flags = .{},
             .image = image,
             .view_type = .@"2d",
             .format = format,
@@ -219,10 +216,10 @@ const SwapImage = struct {
         }, null);
         errdefer gc.vkd.destroyImageView(gc.dev, view, null);
 
-        const image_acquired = try gc.vkd.createSemaphore(gc.dev, &.{ .flags = .{} }, null);
+        const image_acquired = try gc.vkd.createSemaphore(gc.dev, &.{}, null);
         errdefer gc.vkd.destroySemaphore(gc.dev, image_acquired, null);
 
-        const render_finished = try gc.vkd.createSemaphore(gc.dev, &.{ .flags = .{} }, null);
+        const render_finished = try gc.vkd.createSemaphore(gc.dev, &.{}, null);
         errdefer gc.vkd.destroySemaphore(gc.dev, render_finished, null);
 
         const frame_fence = try gc.vkd.createFence(gc.dev, &.{ .flags = .{ .signaled_bit = true } }, null);
diff --git a/examples/triangle.zig b/examples/triangle.zig
index 72c3848..df4e70e 100644
--- a/examples/triangle.zig
+++ b/examples/triangle.zig
@@ -92,18 +92,14 @@ pub fn main() !void {
     defer destroyFramebuffers(&gc, allocator, framebuffers);
 
     const pool = try gc.vkd.createCommandPool(gc.dev, &.{
-        .flags = .{},
         .queue_family_index = gc.graphics_queue.family,
     }, null);
     defer gc.vkd.destroyCommandPool(gc.dev, pool, null);
 
     const buffer = try gc.vkd.createBuffer(gc.dev, &.{
-        .flags = .{},
         .size = @sizeOf(@TypeOf(vertices)),
         .usage = .{ .transfer_dst_bit = true, .vertex_buffer_bit = true },
         .sharing_mode = .exclusive,
-        .queue_family_index_count = 0,
-        .p_queue_family_indices = undefined,
     }, null);
     defer gc.vkd.destroyBuffer(gc.dev, buffer, null);
     const mem_reqs = gc.vkd.getBufferMemoryRequirements(gc.dev, buffer);
@@ -166,12 +162,9 @@ pub fn main() !void {
 
 fn uploadVertices(gc: *const GraphicsContext, pool: vk.CommandPool, buffer: vk.Buffer) !void {
     const staging_buffer = try gc.vkd.createBuffer(gc.dev, &.{
-        .flags = .{},
         .size = @sizeOf(@TypeOf(vertices)),
         .usage = .{ .transfer_src_bit = true },
         .sharing_mode = .exclusive,
-        .queue_family_index_count = 0,
-        .p_queue_family_indices = undefined,
     }, null);
     defer gc.vkd.destroyBuffer(gc.dev, staging_buffer, null);
     const mem_reqs = gc.vkd.getBufferMemoryRequirements(gc.dev, staging_buffer);
@@ -203,7 +196,6 @@ fn copyBuffer(gc: *const GraphicsContext, pool: vk.CommandPool, dst: vk.Buffer,
 
     try gc.vkd.beginCommandBuffer(cmdbuf, &.{
         .flags = .{ .one_time_submit_bit = true },
-        .p_inheritance_info = null,
     });
 
     const region = vk.BufferCopy{
@@ -216,13 +208,8 @@ fn copyBuffer(gc: *const GraphicsContext, pool: vk.CommandPool, dst: vk.Buffer,
     try gc.vkd.endCommandBuffer(cmdbuf);
 
     const si = vk.SubmitInfo{
-        .wait_semaphore_count = 0,
-        .p_wait_semaphores = undefined,
-        .p_wait_dst_stage_mask = undefined,
         .command_buffer_count = 1,
         .p_command_buffers = @ptrCast([*]const vk.CommandBuffer, &cmdbuf),
-        .signal_semaphore_count = 0,
-        .p_signal_semaphores = undefined,
     };
     try gc.vkd.queueSubmit(gc.graphics_queue.handle, 1, @ptrCast([*]const vk.SubmitInfo, &si), .null_handle);
     try gc.vkd.queueWaitIdle(gc.graphics_queue.handle);
@@ -267,10 +254,7 @@ fn createCommandBuffers(
     };
 
     for (cmdbufs) |cmdbuf, i| {
-        try gc.vkd.beginCommandBuffer(cmdbuf, &.{
-            .flags = .{},
-            .p_inheritance_info = null,
-        });
+        try gc.vkd.beginCommandBuffer(cmdbuf, &.{});
 
         gc.vkd.cmdSetViewport(cmdbuf, 0, 1, @ptrCast([*]const vk.Viewport, &viewport));
         gc.vkd.cmdSetScissor(cmdbuf, 0, 1, @ptrCast([*]const vk.Rect2D, &scissor));
@@ -315,7 +299,6 @@ fn createFramebuffers(gc: *const GraphicsContext, allocator: Allocator, render_p
 
     for (framebuffers) |*fb| {
         fb.* = try gc.vkd.createFramebuffer(gc.dev, &.{
-            .flags = .{},
             .render_pass = render_pass,
             .attachment_count = 1,
             .p_attachments = @ptrCast([*]const vk.ImageView, &swapchain.swap_images[i].view),
@@ -336,7 +319,6 @@ fn destroyFramebuffers(gc: *const GraphicsContext, allocator: Allocator, framebu
 
 fn createRenderPass(gc: *const GraphicsContext, swapchain: Swapchain) !vk.RenderPass {
     const color_attachment = vk.AttachmentDescription{
-        .flags = .{},
         .format = swapchain.surface_format.format,
         .samples = .{ .@"1_bit" = true },
         .load_op = .clear,
@@ -353,26 +335,16 @@ fn createRenderPass(gc: *const GraphicsContext, swapchain: Swapchain) !vk.Render
     };
 
     const subpass = vk.SubpassDescription{
-        .flags = .{},
         .pipeline_bind_point = .graphics,
-        .input_attachment_count = 0,
-        .p_input_attachments = undefined,
         .color_attachment_count = 1,
         .p_color_attachments = @ptrCast([*]const vk.AttachmentReference, &color_attachment_ref),
-        .p_resolve_attachments = null,
-        .p_depth_stencil_attachment = null,
-        .preserve_attachment_count = 0,
-        .p_preserve_attachments = undefined,
     };
 
     return try gc.vkd.createRenderPass(gc.dev, &.{
-        .flags = .{},
         .attachment_count = 1,
         .p_attachments = @ptrCast([*]const vk.AttachmentDescription, &color_attachment),
         .subpass_count = 1,
         .p_subpasses = @ptrCast([*]const vk.SubpassDescription, &subpass),
-        .dependency_count = 0,
-        .p_dependencies = undefined,
     }, null);
 }
 
@@ -382,14 +354,12 @@ fn createPipeline(
     render_pass: vk.RenderPass,
 ) !vk.Pipeline {
     const vert = try gc.vkd.createShaderModule(gc.dev, &.{
-        .flags = .{},
         .code_size = shaders.triangle_vert.len,
         .p_code = @ptrCast([*]const u32, &shaders.triangle_vert),
     }, null);
     defer gc.vkd.destroyShaderModule(gc.dev, vert, null);
 
     const frag = try gc.vkd.createShaderModule(gc.dev, &.{
-        .flags = .{},
         .code_size = shaders.triangle_frag.len,
         .p_code = @ptrCast([*]const u32, &shaders.triangle_frag),
     }, null);
@@ -397,23 +367,18 @@ fn createPipeline(
 
     const pssci = [_]vk.PipelineShaderStageCreateInfo{
         .{
-            .flags = .{},
             .stage = .{ .vertex_bit = true },
             .module = vert,
             .p_name = "main",
-            .p_specialization_info = null,
         },
         .{
-            .flags = .{},
             .stage = .{ .fragment_bit = true },
             .module = frag,
             .p_name = "main",
-            .p_specialization_info = null,
         },
     };
 
     const pvisci = vk.PipelineVertexInputStateCreateInfo{
-        .flags = .{},
         .vertex_binding_description_count = 1,
         .p_vertex_binding_descriptions = @ptrCast([*]const vk.VertexInputBindingDescription, &Vertex.binding_description),
         .vertex_attribute_description_count = Vertex.attribute_description.len,
@@ -421,13 +386,11 @@ fn createPipeline(
     };
 
     const piasci = vk.PipelineInputAssemblyStateCreateInfo{
-        .flags = .{},
         .topology = .triangle_list,
         .primitive_restart_enable = vk.FALSE,
     };
 
     const pvsci = vk.PipelineViewportStateCreateInfo{
-        .flags = .{},
         .viewport_count = 1,
         .p_viewports = undefined, // set in createCommandBuffers with cmdSetViewport
         .scissor_count = 1,
@@ -435,7 +398,6 @@ fn createPipeline(
     };
 
     const prsci = vk.PipelineRasterizationStateCreateInfo{
-        .flags = .{},
         .depth_clamp_enable = vk.FALSE,
         .rasterizer_discard_enable = vk.FALSE,
         .polygon_mode = .fill,
@@ -449,11 +411,9 @@ fn createPipeline(
     };
 
     const pmsci = vk.PipelineMultisampleStateCreateInfo{
-        .flags = .{},
         .rasterization_samples = .{ .@"1_bit" = true },
         .sample_shading_enable = vk.FALSE,
         .min_sample_shading = 1,
-        .p_sample_mask = null,
         .alpha_to_coverage_enable = vk.FALSE,
         .alpha_to_one_enable = vk.FALSE,
     };
@@ -470,7 +430,6 @@ fn createPipeline(
     };
 
     const pcbsci = vk.PipelineColorBlendStateCreateInfo{
-        .flags = .{},
         .logic_op_enable = vk.FALSE,
         .logic_op = .copy,
         .attachment_count = 1,
diff --git a/generator/vulkan/c_parse.zig b/generator/vulkan/c_parse.zig
index dd85b24..4b34ca9 100644
--- a/generator/vulkan/c_parse.zig
+++ b/generator/vulkan/c_parse.zig
@@ -263,6 +263,7 @@ pub fn parseMember(allocator: Allocator, xctok: *XmlCTokenizer, ptrs_optional: b
         .field_type = decl.decl_type,
         .bits = null,
         .is_buffer_len = false,
+        .is_optional = false,
     };
 
     if (try xctok.peek()) |tok| {
diff --git a/generator/vulkan/parse.zig b/generator/vulkan/parse.zig
index d369444..46e8188 100644
--- a/generator/vulkan/parse.zig
+++ b/generator/vulkan/parse.zig
@@ -199,6 +199,15 @@ fn parseContainer(allocator: Allocator, ty: *xml.Element, is_union: bool) !regis
             }
         }
 
+        if (member.getAttribute("optional")) |optionals| {
+            var optional_it = mem.split(u8, optionals, ",");
+            if (optional_it.next()) |first_optional| {
+                members[i].is_optional = mem.eql(u8, first_optional, "true");
+            } else {
+                // Optional is empty, probably incorrect.
+                return error.InvalidRegistry;
+            }
+        }
         i += 1;
     }
 
@@ -245,7 +254,7 @@ fn parseFuncPointer(allocator: Allocator, ty: *xml.Element) !registry.Declaratio
     return try cparse.parseTypedef(allocator, &xctok, true);
 }
 
-// For some reason, the DeclarationType cannot be passed to lenToPointerSize, as
+// For some reason, the DeclarationType cannot be passed to lenToPointer, as
 // that causes the Zig compiler to generate invalid code for the function. Using a
 // dedicated enum fixes the issue...
 const Fields = union(enum) {
@@ -253,13 +262,14 @@ const Fields = union(enum) {
     container: []registry.Container.Field,
 };
 
-fn lenToPointerSize(fields: Fields, len: []const u8) registry.Pointer.PointerSize {
+// returns .{ size, nullable }
+fn lenToPointer(fields: Fields, len: []const u8) std.meta.Tuple(&.{ registry.Pointer.PointerSize, bool }) {
     switch (fields) {
         .command => |params| {
             for (params) |*param| {
                 if (mem.eql(u8, param.name, len)) {
                     param.is_buffer_len = true;
-                    return .{ .other_field = param.name };
+                    return .{ .{ .other_field = param.name }, false };
                 }
             }
         },
@@ -267,16 +277,16 @@ fn lenToPointerSize(fields: Fields, len: []const u8) registry.Pointer.PointerSiz
             for (members) |*member| {
                 if (mem.eql(u8, member.name, len)) {
                     member.is_buffer_len = true;
-                    return .{ .other_field = member.name };
+                    return .{ .{ .other_field = member.name }, member.is_optional };
                 }
             }
         },
     }
 
     if (mem.eql(u8, len, "null-terminated")) {
-        return .zero_terminated;
+        return .{ .zero_terminated, false };
     } else {
-        return .many;
+        return .{ .many, false };
     }
 }
 
@@ -286,7 +296,11 @@ fn parsePointerMeta(fields: Fields, type_info: *registry.TypeInfo, elem: *xml.El
         var current_type_info = type_info;
         while (current_type_info.* == .pointer) {
             // TODO: Check altlen
-            const size = if (it.next()) |len_str| lenToPointerSize(fields, len_str) else .many;
+            const size = if (it.next()) |len_str| blk: {
+                const size_optional = lenToPointer(fields, len_str);
+                current_type_info.pointer.is_optional = size_optional[1];
+                break :blk size_optional[0];
+            }  else .many;
             current_type_info.pointer.size = size;
             current_type_info = current_type_info.pointer.child;
         }
diff --git a/generator/vulkan/registry.zig b/generator/vulkan/registry.zig
index 70c779e..dfaac2c 100644
--- a/generator/vulkan/registry.zig
+++ b/generator/vulkan/registry.zig
@@ -61,6 +61,7 @@ pub const Container = struct {
         field_type: TypeInfo,
         bits: ?usize,
         is_buffer_len: bool,
+        is_optional: bool,
     };
 
     stype: ?[]const u8,
diff --git a/generator/vulkan/render.zig b/generator/vulkan/render.zig
index 51a72a1..39e0978 100644
--- a/generator/vulkan/render.zig
+++ b/generator/vulkan/render.zig
@@ -749,7 +749,9 @@ fn Renderer(comptime WriterType: type) type {
                     }
                 } else {
                     try self.renderTypeInfo(field.field_type);
-                    try self.renderContainerDefaultField(name, container, field);
+                    if (!container.is_union) {
+                        try self.renderContainerDefaultField(name, container, field);
+                    }
                     try self.writer.writeAll(", ");
                 }
             }
@@ -758,9 +760,7 @@ fn Renderer(comptime WriterType: type) type {
         }
 
         fn renderContainerDefaultField(self: *Self, name: []const u8, container: reg.Container, field: reg.Container.Field) !void {
-            if (mem.eql(u8, field.name, "pNext")) {
-                try self.writer.writeAll(" = null");
-            } else if (mem.eql(u8, field.name, "sType")) {
+            if (mem.eql(u8, field.name, "sType")) {
                 if (container.stype == null) {
                     return;
                 }
@@ -776,8 +776,30 @@ fn Renderer(comptime WriterType: type) type {
 
                 try self.writer.writeAll(" = .");
                 try self.writeIdentifierWithCase(.snake, stype["VK_STRUCTURE_TYPE_".len..]);
-            } else if (field.field_type == .name and !container.is_union and mem.eql(u8, "VkBool32", field.field_type.name) and isFeatureStruct(name, container.extends)) {
+            } else if (field.field_type == .name and mem.eql(u8, "VkBool32", field.field_type.name) and isFeatureStruct(name, container.extends)) {
                 try self.writer.writeAll(" = FALSE");
+            } else if (field.is_optional) {
+                if (field.field_type == .name) {
+                    const field_type_name = field.field_type.name;
+                    if (self.resolveDeclaration(field_type_name)) |decl_type| {
+                        if (decl_type == .handle) {
+                            try self.writer.writeAll(" = .null_handle");
+                        } else if (decl_type == .bitmask) {
+                            try self.writer.writeAll(" = .{}");
+                        } else if (decl_type == .typedef and decl_type.typedef == .command_ptr) {
+                            try self.writer.writeAll(" = null");
+                        } else if ((decl_type == .typedef and builtin_types.has(decl_type.typedef.name)) or
+                            (decl_type == .foreign and builtin_types.has(field_type_name)))
+                        {
+                            try self.writer.writeAll(" = 0");
+                        }
+                    }
+                } else if (field.field_type == .pointer) {
+                    try self.writer.writeAll(" = null");
+                }
+            } else if (field.field_type == .pointer and field.field_type.pointer.is_optional) {
+                // pointer nullability could be here or above
+                try self.writer.writeAll(" = null");
             }
         }