diff --git a/glfw/src/vulkan.zig b/glfw/src/vulkan.zig
index f921f483..4b59bfda 100644
--- a/glfw/src/vulkan.zig
+++ b/glfw/src/vulkan.zig
@@ -34,7 +34,10 @@ pub fn initVulkanLoader(loader_function: ?VKGetInstanceProcAddr) void {
     c.glfwInitVulkanLoader(loader_function orelse null);
 }
 
-pub const VKGetInstanceProcAddr = fn (vk_instance: c.VkInstance, name: [*c]const u8) callconv(.C) ?VKProc;
+pub const VKGetInstanceProcAddr = if (@import("builtin").zig_backend == .stage1)
+    fn (vk_instance: c.VkInstance, name: [*c]const u8) callconv(.C) ?VKProc
+else
+    *const fn (vk_instance: c.VkInstance, name: [*c]const u8) callconv(.C) ?VKProc;
 
 /// Returns whether the Vulkan loader and an ICD have been found.
 ///
@@ -103,7 +106,10 @@ pub inline fn getRequiredInstanceExtensions() error{APIUnavailable}![][*:0]const
 /// Generic function pointer used for returning Vulkan API function pointers.
 ///
 /// see also: vulkan_proc, glfw.getInstanceProcAddress
-pub const VKProc = fn () callconv(.C) void;
+pub const VKProc = if (@import("builtin").zig_backend == .stage1)
+    fn () callconv(.C) void
+else
+    *const fn () callconv(.C) void;
 
 /// Returns the address of the specified Vulkan instance function.
 ///