diff --git a/src/device.rs b/src/device.rs
index ef87961..bddd982 100644
--- a/src/device.rs
+++ b/src/device.rs
@@ -7,6 +7,7 @@ use ::RawPtr;
 unsafe impl Sync for Device {}
 unsafe impl Send for Device {}
 
+#[derive(Clone)]
 pub struct Device {
     handle: vk::Device,
     device_fn: vk::DeviceFn,
diff --git a/src/entry.rs b/src/entry.rs
index b988870..f43b377 100644
--- a/src/entry.rs
+++ b/src/entry.rs
@@ -33,14 +33,14 @@ pub struct Entry {
 
 #[derive(Debug)]
 pub enum LoadingError {
-    LibraryLoadFailure(String),
-    StaticLoadError(String),
-    EntryLoadError(String),
+    LibraryLoadError(String),
+    EntryLoadError(Vec<&'static str>),
+    StaticLoadError(Vec<&'static str>),
 }
 
 #[derive(Debug)]
 pub enum InstanceError {
-    LoadError(String),
+    LoadError(Vec<&'static str>),
     VkError(vk::Result),
 }
 
@@ -58,7 +58,7 @@ impl Entry {
                     }).map_err(|err| LoadingError::StaticLoadError(err))?;
                 Ok(static_fn)
             }
-            Err(ref err) => Err(LoadingError::LibraryLoadFailure(err.clone())),
+            Err(ref err) => Err(LoadingError::LibraryLoadError(err.clone())),
         }?;
         let entry_fn = vk::EntryFn::load(|name| unsafe {
                 mem::transmute(static_fn.get_instance_proc_addr(vk::Instance::null(), name.as_ptr()))
diff --git a/src/extensions/android_surface.rs b/src/extensions/android_surface.rs
index 7fec956..876be1e 100644
--- a/src/extensions/android_surface.rs
+++ b/src/extensions/android_surface.rs
@@ -13,7 +13,7 @@ pub struct AndroidSurface {
 }
 
 impl AndroidSurface {
-    pub fn new(entry: &Entry, instance: &Instance) -> Result<AndroidSurface, String> {
+    pub fn new(entry: &Entry, instance: &Instance) -> Result<AndroidSurface, Vec<&'static str>> {
         let surface_fn = vk::AndroidSurfaceFn::load(|name| {
             unsafe {
                 mem::transmute(entry.get_instance_proc_addr(instance.handle(), name.as_ptr()))
diff --git a/src/extensions/debug_report.rs b/src/extensions/debug_report.rs
index 4f0b37d..d8f37cb 100644
--- a/src/extensions/debug_report.rs
+++ b/src/extensions/debug_report.rs
@@ -12,7 +12,7 @@ pub struct DebugReport {
 }
 
 impl DebugReport {
-    pub fn new(entry: &Entry, instance: &Instance) -> Result<DebugReport, String> {
+    pub fn new(entry: &Entry, instance: &Instance) -> Result<DebugReport, Vec<&'static str>> {
         let debug_report_fn = vk::DebugReportFn::load(|name| {
             unsafe {
                 mem::transmute(entry.get_instance_proc_addr(instance.handle(), name.as_ptr()))
diff --git a/src/extensions/mir_surface.rs b/src/extensions/mir_surface.rs
index bc54833..1f3da67 100644
--- a/src/extensions/mir_surface.rs
+++ b/src/extensions/mir_surface.rs
@@ -13,7 +13,7 @@ pub struct MirSurface {
 }
 
 impl MirSurface {
-    pub fn new(entry: &Entry, instance: &Instance) -> Result<MirSurface, String> {
+    pub fn new(entry: &Entry, instance: &Instance) -> Result<MirSurface, Vec<&'static str>> {
         let surface_fn = vk::MirSurfaceFn::load(|name| {
             unsafe {
                 mem::transmute(entry.get_instance_proc_addr(instance.handle(), name.as_ptr()))
diff --git a/src/extensions/mod.rs b/src/extensions/mod.rs
index b782dbc..9ed6c99 100644
--- a/src/extensions/mod.rs
+++ b/src/extensions/mod.rs
@@ -11,8 +11,8 @@ pub use self::android_surface::AndroidSurface;
 mod swapchain;
 mod surface;
 mod xlibsurface;
-mod debug_report;
 mod win32_surface;
+mod debug_report;
 mod mir_surface;
 mod android_surface;
 mod wayland_surface;
diff --git a/src/extensions/surface.rs b/src/extensions/surface.rs
index e09910e..0807437 100644
--- a/src/extensions/surface.rs
+++ b/src/extensions/surface.rs
@@ -14,7 +14,7 @@ pub struct Surface {
 }
 
 impl Surface {
-    pub fn new(entry: &Entry, instance: &Instance) -> Result<Surface, String> {
+    pub fn new(entry: &Entry, instance: &Instance) -> Result<Surface, Vec<&'static str>> {
         let surface_fn = vk::SurfaceFn::load(|name| {
             unsafe {
                 mem::transmute(entry.get_instance_proc_addr(instance.handle(), name.as_ptr()))
diff --git a/src/extensions/swapchain.rs b/src/extensions/swapchain.rs
index 18746ab..c2fdf28 100644
--- a/src/extensions/swapchain.rs
+++ b/src/extensions/swapchain.rs
@@ -13,7 +13,7 @@ pub struct Swapchain {
 }
 
 impl Swapchain {
-    pub fn new(instance: &Instance, device: &Device) -> Result<Swapchain, String> {
+    pub fn new(instance: &Instance, device: &Device) -> Result<Swapchain, Vec<&'static str>> {
         let swapchain_fn = vk::SwapchainFn::load(|name| {
             unsafe { mem::transmute(instance.get_device_proc_addr(device.handle(), name.as_ptr())) }
         })?;
diff --git a/src/extensions/wayland_surface.rs b/src/extensions/wayland_surface.rs
index 8f59120..eb851c5 100644
--- a/src/extensions/wayland_surface.rs
+++ b/src/extensions/wayland_surface.rs
@@ -12,7 +12,7 @@ pub struct WaylandSurface {
 }
 
 impl WaylandSurface {
-    pub fn new(entry: &Entry, instance: &Instance) -> Result<WaylandSurface, String> {
+    pub fn new(entry: &Entry, instance: &Instance) -> Result<WaylandSurface, Vec<&'static str>> {
         let surface_fn = vk::WaylandSurfaceFn::load(|name| {
             unsafe {
                 mem::transmute(entry.get_instance_proc_addr(instance.handle(), name.as_ptr()))
diff --git a/src/extensions/win32_surface.rs b/src/extensions/win32_surface.rs
index dbffc9e..e5f2f86 100644
--- a/src/extensions/win32_surface.rs
+++ b/src/extensions/win32_surface.rs
@@ -13,7 +13,7 @@ pub struct Win32Surface {
 }
 
 impl Win32Surface {
-    pub fn new(entry: &Entry, instance: &Instance) -> Result<Win32Surface, String> {
+    pub fn new(entry: &Entry, instance: &Instance) -> Result<Win32Surface, Vec<&'static str>> {
         let surface_fn = vk::Win32SurfaceFn::load(|name| {
             unsafe {
                 mem::transmute(entry.get_instance_proc_addr(instance.handle(), name.as_ptr()))
diff --git a/src/extensions/xcb_surface.rs b/src/extensions/xcb_surface.rs
index 8b8f818..64890d0 100644
--- a/src/extensions/xcb_surface.rs
+++ b/src/extensions/xcb_surface.rs
@@ -13,7 +13,7 @@ pub struct XcbSurface {
 }
 
 impl XcbSurface {
-    pub fn new(entry: &Entry, instance: &Instance) -> Result<XcbSurface, String> {
+    pub fn new(entry: &Entry, instance: &Instance) -> Result<XcbSurface, Vec<&'static str>> {
         let surface_fn = vk::XcbSurfaceFn::load(|name| {
             unsafe {
                 mem::transmute(entry.get_instance_proc_addr(instance.handle(), name.as_ptr()))
diff --git a/src/extensions/xlibsurface.rs b/src/extensions/xlibsurface.rs
index 1ea3f8e..f8809fa 100644
--- a/src/extensions/xlibsurface.rs
+++ b/src/extensions/xlibsurface.rs
@@ -13,7 +13,7 @@ pub struct XlibSurface {
 }
 
 impl XlibSurface {
-    pub fn new(entry: &Entry, instance: &Instance) -> Result<XlibSurface, String> {
+    pub fn new(entry: &Entry, instance: &Instance) -> Result<XlibSurface, Vec<&'static str>> {
         let surface_fn = vk::XlibSurfaceFn::load(|name| {
             unsafe {
                 mem::transmute(entry.get_instance_proc_addr(instance.handle(), name.as_ptr()))
diff --git a/src/instance.rs b/src/instance.rs
index bef667c..67a4e62 100644
--- a/src/instance.rs
+++ b/src/instance.rs
@@ -8,11 +8,11 @@ use ::RawPtr;
 
 #[derive(Debug)]
 pub enum DeviceError {
-    LoadError(String),
+    LoadError(Vec<&'static str>),
     VkError(vk::Result),
 }
 
-#[derive(Debug)]
+#[derive(Clone)]
 pub struct Instance {
     handle: vk::Instance,
     instance_fn: vk::InstanceFn,
diff --git a/src/vk.rs b/src/vk.rs
index 39f0057..df4e124 100644
--- a/src/vk.rs
+++ b/src/vk.rs
@@ -3658,48 +3658,40 @@ macro_rules! vk_functions {
         unsafe impl Sync for $struct_name {}
 
         impl $struct_name {
-            pub fn load<F>(mut f: F) -> ::std::result::Result<$struct_name, String>
+            pub fn load<F>(mut f: F) -> ::std::result::Result<$struct_name, Vec<&'static str>>
                 where F: FnMut(&::std::ffi::CStr) -> *const c_void
             {
                 use std::ffi::{CString};
                 use std::mem;
+                let mut err_str = Vec::new();
                 let s = $struct_name {
                     $(
                         $name: unsafe {
                             let cname = CString::new($raw_name).unwrap();
                             let val = f(&cname);
+                            if val.is_null(){
+                                err_str.push(stringify!($raw_name));
+                            }
                             mem::transmute(val)
                         },
                     )+
                 };
-                ::std::result::Result::Ok(s)
+
+                if err_str.is_empty() {
+                    Ok(s)
+                }
+                else{
+                    Err(err_str)
+                }
             }
             $(
                 #[inline]
                 pub unsafe fn $name(&self $(, $param_name: $param)*) -> $ret {
                     let fp = self.$name;
-                    debug_assert!(!(self.$name as *const c_void).is_null(), "{} not loaded!.", stringify!($raw_name));
                     fp($($param_name),*)
                 }
             )+
         }
-        impl ::std::fmt::Debug for $struct_name {
-            #[inline]
-            fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::result::Result<(), ::std::fmt::Error> {
-                writeln!(fmt, stringify!($struct_name))?;
-                $(
-                    if !(self.$name as *const c_void).is_null() {
-                        write!(fmt," Is loaded => " )?;
-                    }
-                    else{
-                        write!(fmt," Is not loaded => " )?;
-                    }
-                    write!(fmt, $raw_name)?;
-                    writeln!(fmt, ", ")?;
-                )+
-                write!(fmt, "")
-            }
-        }
     }
 }
 
@@ -4830,7 +4822,6 @@ vk_functions!{
         p_allocator: *const AllocationCallbacks,
         p_surface: *mut SurfaceKHR,
     ) -> Result;
-
 }
 vk_functions!{
     WaylandSurfaceFn,