diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..4871ef8
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+deps/deps.jl
diff --git a/.travis.yml b/.travis.yml
index 505e010..046994f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,6 +5,10 @@ dist: trusty
 julia:
   - 0.7
   - nightly
+matrix:
+  allow_failures:
+    - julia: nightly
+
 notifications:
   email: false
 addons:
diff --git a/README.md b/README.md
index 6772538..c32b7a4 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,15 @@ OpenGL bindings for OpenGL 3.0 and upwards. As OpenGL 3.0 has a lot of overlaps
 
 The philosophy is to keep this library strictly a low-level wrapper, so you won't find any error handling (besides for the function loading itself) or abstractions in this package.
 
+### Debugging
+
+You can rebuild ModernGL to include debug error checks:
+```Julia
+ENV["MODERNGL_DEBUGGING"] = "true"; Pkg.build("ModernGL")
+# or to get back the default behaviour:
+ENV["MODERNGL_DEBUGGING"] = "false"; Pkg.build("ModernGL")
+```
+
 ### Installation notes
 There are no dependencies, besides the graphic driver. If you have any problems, you should consider updating the driver first.
 
@@ -38,7 +47,7 @@ getProcAddress can be changed like this:
 using ModernGL
 
 function ModernGL.getprocaddress(name::ASCIIString)
-	# for example change it to GLUT 
+	# for example change it to GLUT
 	glutGetProcAddress(name)
 end
 ```
@@ -53,4 +62,4 @@ It seems, that there is actually no good way of testing if a function is support
 Credits go certainly to the OpenGL.jl ([rennis250](https://github.com/rennis250) && [o-jasper](https://github.com/o-jasper)) package, where I have all the OpenGL definitions from.
 Special thanks to rennis250 for all the support! :)
 
-Also, I have to thank for the constructive discussion on Julia-Users, where I got a good solution for the function pointer loading (final solution was from [vtjnash](https://github.com/vtjnash) and got replaced by [aaalexandrov's](https://github.com/aaalexandrov/) solution which doubled the speed). 
+Also, I have to thank for the constructive discussion on Julia-Users, where I got a good solution for the function pointer loading (final solution was from [vtjnash](https://github.com/vtjnash) and got replaced by [aaalexandrov's](https://github.com/aaalexandrov/) solution which doubled the speed).
diff --git a/appveyor.yml b/appveyor.yml
index 93aa461..bd2f18c 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -14,6 +14,11 @@ notifications:
     on_build_failure: false
     on_build_status_changed: false
 
+matrix:
+  allow_failures:
+  - JULIA_URL: "https://julialangnightlies-s3.julialang.org/bin/winnt/x86/julia-latest-win32.exe"
+  - JULIA_URL: "https://julialangnightlies-s3.julialang.org/bin/winnt/x64/julia-latest-win64.exe"
+
 install:
   - ps: "[System.Net.ServicePointManager]::SecurityProtocol = [System.Net.SecurityProtocolType]::Tls12"
 # Download most recent Julia Windows binary
diff --git a/deps/build.jl b/deps/build.jl
new file mode 100644
index 0000000..fc4fb98
--- /dev/null
+++ b/deps/build.jl
@@ -0,0 +1,4 @@
+debug_level = get(ENV, "MODERNGL_DEBUGGING", "false") == "true"
+open(joinpath(@__DIR__, "deps.jl"), "w") do io
+    println(io, "const enable_opengl_debugging = $debug_level")
+end
diff --git a/deps/deps.jl b/deps/deps.jl
new file mode 100644
index 0000000..064f0e2
--- /dev/null
+++ b/deps/deps.jl
@@ -0,0 +1 @@
+const enable_opengl_debugging = false
diff --git a/src/functionloading.jl b/src/functionloading.jl
index e406c64..6c8346d 100644
--- a/src/functionloading.jl
+++ b/src/functionloading.jl
@@ -1,6 +1,27 @@
 mutable struct GLFunc
     p::Ptr{Cvoid}
 end
+
+include(joinpath("..", "deps", "deps.jl"))
+
+gl_represent(x::GLenum) = GLENUM(x).name
+gl_represent(x) = repr(x)
+
+function debug_opengl_expr(func_name, args)
+    if enable_opengl_debugging && func_name != :glGetError
+        quote
+            err = glGetError()
+            if err != GL_NO_ERROR
+                arguments = gl_represent.(tuple($(args...)))
+                warn("OpenGL call to $($func_name), with arguments: $(arguments)
+                Failed with error: $(GLENUM(err).name).")
+            end
+        end
+    else
+        :()
+    end
+end
+
 # based on getCFun macro
 macro glfunc(opengl_func)
     arguments = map(opengl_func.args[1].args[2:end]) do arg
@@ -22,7 +43,9 @@ macro glfunc(opengl_func)
             ptr_expr = :(($func_name_sym, "opengl32"))
             ret = quote
                 function $func_name($(arg_names...))
-                    ccall($ptr_expr, $return_type, ($(input_types...),), $(arg_names...))
+                    result = ccall($ptr_expr, $return_type, ($(input_types...),), $(arg_names...))
+                    $(debug_opengl_expr(func_name, arg_names))
+                    result
                 end
                 $(Expr(:export, func_name))
             end
@@ -36,12 +59,15 @@ macro glfunc(opengl_func)
             if $ptr_sym.p::Ptr{Cvoid} == C_NULL
                 $ptr_sym.p::Ptr{Cvoid} = $ptr_expr
             end
-            ccall($ptr_sym.p::Ptr{Cvoid}, $return_type, ($(input_types...),), $(arg_names...))
+            result = ccall($ptr_sym.p::Ptr{Cvoid}, $return_type, ($(input_types...),), $(arg_names...))
+            $(debug_opengl_expr(func_name, arg_names))
+            result
         end
         $(Expr(:export, func_name))
         end
     return esc(ret)
 end
+
 if Sys.iswindows()
     const gl_lib = Libdl.dlopen("opengl32")
 end