Clean up error handling

12 files changed, 123 insertions, 114 deletions

diff --git a/pugl/detail/implementation.c b/pugl/detail/implementation.c
index f1fd57a..6375444 100644
--- a/pugl/detail/implementation.c
+++ b/pugl/detail/implementation.c
@@ -306,7 +306,7 @@ puglSetInternalClipboard(PuglView* const   view,
                          const size_t      len)
 {
 	if (type && strcmp(type, "text/plain")) {
-		return PUGL_ERR_UNSUPPORTED_TYPE;
+		return PUGL_UNSUPPORTED_TYPE;
 	}
 
 	puglSetBlob(&view->clipboard, data, len);
diff --git a/pugl/detail/mac_cairo.m b/pugl/detail/mac_cairo.m
index fcb4f07..143fbb0 100644
--- a/pugl/detail/mac_cairo.m
+++ b/pugl/detail/mac_cairo.m
@@ -61,13 +61,13 @@
 
 @end
 
-static int
+static PuglStatus
 puglMacCairoConfigure(PuglView* PUGL_UNUSED(view))
 {
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglMacCairoCreate(PuglView* view)
 {
 	PuglInternals* impl     = view->impl;
@@ -82,10 +82,10 @@ puglMacCairoCreate(PuglView* view)
 	}
 
 	impl->drawView = drawView;
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglMacCairoDestroy(PuglView* view)
 {
 	PuglCairoView* const drawView = (PuglCairoView*)view->impl->drawView;
@@ -94,15 +94,15 @@ puglMacCairoDestroy(PuglView* view)
 	[drawView release];
 
 	view->impl->drawView = nil;
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglMacCairoEnter(PuglView* view, bool drawing)
 {
 	PuglCairoView* const drawView = (PuglCairoView*)view->impl->drawView;
 	if (!drawing) {
-		return 0;
+		return PUGL_SUCCESS;
 	}
 
 	assert(!drawView->surface);
@@ -115,15 +115,15 @@ puglMacCairoEnter(PuglView* view, bool drawing)
 
 	drawView->cr = cairo_create(drawView->surface);
 
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglMacCairoLeave(PuglView* view, bool drawing)
 {
 	PuglCairoView* const drawView = (PuglCairoView*)view->impl->drawView;
 	if (!drawing) {
-		return 0;
+		return PUGL_SUCCESS;
 	}
 
 	assert(drawView->surface);
@@ -138,16 +138,16 @@ puglMacCairoLeave(PuglView* view, bool drawing)
 
 	CGContextFlush(context);
 
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglMacCairoResize(PuglView* PUGL_UNUSED(view),
                    int       PUGL_UNUSED(width),
                    int       PUGL_UNUSED(height))
 {
 	// No need to resize, the surface is created for the drawing context
-	return 0;
+	return PUGL_SUCCESS;
 }
 
 static void*
diff --git a/pugl/detail/mac_gl.m b/pugl/detail/mac_gl.m
index 58d815d..b84f799 100644
--- a/pugl/detail/mac_gl.m
+++ b/pugl/detail/mac_gl.m
@@ -93,13 +93,13 @@ typedef NSUInteger NSWindowStyleMask;
 
 @end
 
-static int
+static PuglStatus
 puglMacGlConfigure(PuglView* PUGL_UNUSED(view))
 {
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglMacGlCreate(PuglView* view)
 {
 	PuglInternals*  impl     = view->impl;
@@ -116,10 +116,10 @@ puglMacGlCreate(PuglView* view)
 	}
 
 	impl->drawView = drawView;
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglMacGlDestroy(PuglView* view)
 {
 	PuglOpenGLView* const drawView = (PuglOpenGLView*)view->impl->drawView;
@@ -128,19 +128,19 @@ puglMacGlDestroy(PuglView* view)
 	[drawView release];
 
 	view->impl->drawView = nil;
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglMacGlEnter(PuglView* view, bool PUGL_UNUSED(drawing))
 {
 	PuglOpenGLView* const drawView = (PuglOpenGLView*)view->impl->drawView;
 
 	[[drawView openGLContext] makeCurrentContext];
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglMacGlLeave(PuglView* view, bool drawing)
 {
 	PuglOpenGLView* const drawView = (PuglOpenGLView*)view->impl->drawView;
@@ -151,17 +151,17 @@ puglMacGlLeave(PuglView* view, bool drawing)
 
 	[NSOpenGLContext clearCurrentContext];
 
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglMacGlResize(PuglView* view, int PUGL_UNUSED(width), int PUGL_UNUSED(height))
 {
 	PuglOpenGLView* const drawView = (PuglOpenGLView*)view->impl->drawView;
 
 	[drawView reshape];
 
-	return 0;
+	return PUGL_SUCCESS;
 }
 
 static void*
diff --git a/pugl/detail/types.h b/pugl/detail/types.h
index 4ac224b..d018be5 100644
--- a/pugl/detail/types.h
+++ b/pugl/detail/types.h
@@ -89,22 +89,22 @@ typedef void PuglSurface;
 /** Graphics backend interface. */
 struct PuglBackendImpl {
 	/** Get visual information from display and setup view as necessary. */
-	int (*configure)(PuglView*);
+	PuglStatus (*configure)(PuglView*);
 
 	/** Create surface and drawing context. */
-	int (*create)(PuglView*);
+	PuglStatus (*create)(PuglView*);
 
 	/** Destroy surface and drawing context. */
-	int (*destroy)(PuglView*);
+	PuglStatus (*destroy)(PuglView*);
 
 	/** Enter drawing context, for drawing if parameter is true. */
-	int (*enter)(PuglView*, bool);
+	PuglStatus (*enter)(PuglView*, bool);
 
 	/** Leave drawing context, after drawing if parameter is true. */
-	int (*leave)(PuglView*, bool);
+	PuglStatus (*leave)(PuglView*, bool);
 
 	/** Resize drawing context to the given width and height. */
-	int (*resize)(PuglView*, int, int);
+	PuglStatus (*resize)(PuglView*, int, int);
 
 	/** Return the puglGetContext() handle for the application, if any. */
 	void* (*getContext)(PuglView*);
diff --git a/pugl/detail/win.c b/pugl/detail/win.c
index 25780e0..90c133f 100644
--- a/pugl/detail/win.c
+++ b/pugl/detail/win.c
@@ -163,18 +163,18 @@ puglCreateWindow(PuglView* view, const char* title)
 
 	// Register window class if necessary
 	if (!puglRegisterWindowClass(view->world->className)) {
-		return PUGL_ERR_UNKNOWN;
+		return PUGL_REGISTRATION_FAILED;
 	}
 
 	if (!view->backend || !view->backend->configure) {
-		return PUGL_ERR_UNKNOWN;
+		return PUGL_BAD_BACKEND;
 	}
 
-	int st = view->backend->configure(view);
+	PuglStatus st = view->backend->configure(view);
 	if (st || !impl->surface) {
-		return PUGL_ERR_SET_FORMAT;
+		return PUGL_SET_FORMAT_FAILED;
 	} else if ((st = view->backend->create(view))) {
-		return PUGL_ERR_CREATE_CONTEXT;
+		return PUGL_CREATE_CONTEXT_FAILED;
 	}
 
 	if (title) {
@@ -828,7 +828,7 @@ puglSetFrame(PuglView* view, const PuglRect frame)
 		                  rect.left, rect.top,
 		                  rect.right - rect.left, rect.bottom - rect.top,
 		                  (SWP_NOACTIVATE|SWP_NOOWNERZORDER|SWP_NOZORDER))) {
-			return PUGL_ERR_UNKNOWN;
+			return PUGL_UNKNOWN_ERROR;
 		}
 	}
 
@@ -896,7 +896,7 @@ puglSetClipboard(PuglView* const   view,
 	if (st) {
 		return st;
 	} else if (!OpenClipboard(impl->hwnd)) {
-		return PUGL_ERR_UNKNOWN;
+		return PUGL_UNKNOWN_ERROR;
 	}
 
 	// Measure string and allocate global memory for clipboard
@@ -905,7 +905,7 @@ puglSetClipboard(PuglView* const   view,
 	HGLOBAL     mem  = GlobalAlloc(GMEM_MOVEABLE, (wlen + 1) * sizeof(wchar_t));
 	if (!mem) {
 		CloseClipboard();
-		return PUGL_ERR_UNKNOWN;
+		return PUGL_UNKNOWN_ERROR;
 	}
 
 	// Lock global memory
@@ -913,7 +913,7 @@ puglSetClipboard(PuglView* const   view,
 	if (!wstr) {
 		GlobalFree(mem);
 		CloseClipboard();
-		return PUGL_ERR_UNKNOWN;
+		return PUGL_UNKNOWN_ERROR;
 	}
 
 	// Convert string into global memory and set it as clipboard data
diff --git a/pugl/detail/win.h b/pugl/detail/win.h
index b9e554c..6d89759 100644
--- a/pugl/detail/win.h
+++ b/pugl/detail/win.h
@@ -104,11 +104,11 @@ puglWinCreateWindow(const PuglView* const view,
 	                             CW_USEDEFAULT, CW_USEDEFAULT,
 	                             wr.right-wr.left, wr.bottom-wr.top,
 	                             (HWND)view->parent, NULL, NULL, NULL))) {
-		return PUGL_ERR_CREATE_WINDOW;
+		return PUGL_CREATE_WINDOW_FAILED;
 	} else if (!(*hdc = GetDC(*hwnd))) {
 		DestroyWindow(*hwnd);
 		*hwnd = NULL;
-		return PUGL_ERR_CREATE_WINDOW;
+		return PUGL_CREATE_WINDOW_FAILED;
 	}
 
 	return PUGL_SUCCESS;
diff --git a/pugl/detail/win_cairo.c b/pugl/detail/win_cairo.c
index cbca7e8..741f4cf 100644
--- a/pugl/detail/win_cairo.c
+++ b/pugl/detail/win_cairo.c
@@ -51,7 +51,7 @@ puglWinCairoCreateDrawContext(PuglView* view)
 	    (st = cairo_surface_status(surface->surface)) ||
 	    !(surface->cr = cairo_create(surface->surface)) ||
 	    (st = cairo_status(surface->cr))) {
-		return PUGL_ERR_CREATE_CONTEXT;
+		return PUGL_CREATE_CONTEXT_FAILED;
 	}
 
 	cairo_save(surface->cr);
@@ -95,7 +95,7 @@ puglWinCairoConfigure(PuglView* view)
 		DestroyWindow(impl->hwnd);
 		impl->hwnd = NULL;
 		impl->hdc  = NULL;
-		return PUGL_ERR_SET_FORMAT;
+		return PUGL_SET_FORMAT_FAILED;
 	}
 
 	impl->surface = (PuglWinCairoSurface*)calloc(
diff --git a/pugl/detail/win_gl.c b/pugl/detail/win_gl.c
index b7b03a4..db8fee5 100644
--- a/pugl/detail/win_gl.c
+++ b/pugl/detail/win_gl.c
@@ -77,8 +77,8 @@ typedef struct {
 	HDC  hdc;
 } PuglFakeWindow;
 
-static int
-puglWinError(PuglFakeWindow* fakeWin, const int status)
+static PuglStatus
+puglWinError(PuglFakeWindow* fakeWin, const PuglStatus status)
 {
 	if (fakeWin->hwnd) {
 		ReleaseDC(fakeWin->hwnd, fakeWin->hdc);
@@ -102,7 +102,7 @@ static PuglWinGlProcs puglWinGlGetProcs(void)
 	return procs;
 }
 
-static int
+static PuglStatus
 puglWinGlConfigure(PuglView* view)
 {
 	PuglInternals* impl = view->impl;
@@ -140,15 +140,15 @@ puglWinGlConfigure(PuglView* view)
 	const PuglWinPFD fakePfd  = puglWinGetPixelFormatDescriptor(view->hints);
 	const int        fakePfId = ChoosePixelFormat(fakeWin.hdc, &fakePfd);
 	if (!fakePfId) {
-		return puglWinError(&fakeWin, PUGL_ERR_SET_FORMAT);
+		return puglWinError(&fakeWin, PUGL_SET_FORMAT_FAILED);
 	} else if (!SetPixelFormat(fakeWin.hdc, fakePfId, &fakePfd)) {
-		return puglWinError(&fakeWin, PUGL_ERR_SET_FORMAT);
+		return puglWinError(&fakeWin, PUGL_SET_FORMAT_FAILED);
 	}
 
 	// Create fake GL context to get at the functions we need
 	HGLRC fakeRc = wglCreateContext(fakeWin.hdc);
 	if (!fakeRc) {
-		return puglWinError(&fakeWin, PUGL_ERR_CREATE_CONTEXT);
+		return puglWinError(&fakeWin, PUGL_CREATE_CONTEXT_FAILED);
 	}
 
 	// Enter fake context and get extension functions
@@ -160,7 +160,7 @@ puglWinGlConfigure(PuglView* view)
 		UINT numFormats = 0;
 		if (!surface->procs.wglChoosePixelFormat(
 			    fakeWin.hdc, pixelAttrs, NULL, 1u, &impl->pfId, &numFormats)) {
-			return puglWinError(&fakeWin, PUGL_ERR_SET_FORMAT);
+			return puglWinError(&fakeWin, PUGL_SET_FORMAT_FAILED);
 		}
 
 		DescribePixelFormat(
@@ -177,10 +177,10 @@ puglWinGlConfigure(PuglView* view)
 	ReleaseDC(fakeWin.hwnd, fakeWin.hdc);
 	DestroyWindow(fakeWin.hwnd);
 
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglWinGlCreate(PuglView* view)
 {
 	PuglInternals* const    impl    = view->impl;
@@ -205,16 +205,16 @@ puglWinGlCreate(PuglView* view)
 		DestroyWindow(impl->hwnd);
 		impl->hwnd = NULL;
 		impl->hdc  = NULL;
-		return PUGL_ERR_SET_FORMAT;
+		return PUGL_SET_FORMAT_FAILED;
 	}
 
 	// Create GL context
 	if (surface->procs.wglCreateContextAttribs &&
 	    !(surface->hglrc = surface->procs.wglCreateContextAttribs(
 		      impl->hdc, 0, contextAttribs))) {
-		return PUGL_ERR_CREATE_CONTEXT;
+		return PUGL_CREATE_CONTEXT_FAILED;
 	} else if (!(surface->hglrc = wglCreateContext(impl->hdc))) {
-		return PUGL_ERR_CREATE_CONTEXT;
+		return PUGL_CREATE_CONTEXT_FAILED;
 	}
 
 	// Enter context and set swap interval
@@ -223,10 +223,10 @@ puglWinGlCreate(PuglView* view)
 		surface->procs.wglSwapInterval(view->hints[PUGL_SWAP_INTERVAL]);
 	}
 
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglWinGlDestroy(PuglView* view)
 {
 	PuglWinGlSurface* surface = (PuglWinGlSurface*)view->impl->surface;
@@ -237,10 +237,10 @@ puglWinGlDestroy(PuglView* view)
 		view->impl->surface = NULL;
 	}
 
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglWinGlEnter(PuglView* view, bool drawing)
 {
 	PuglWinGlSurface* surface = (PuglWinGlSurface*)view->impl->surface;
@@ -252,10 +252,10 @@ puglWinGlEnter(PuglView* view, bool drawing)
 		BeginPaint(view->impl->hwnd, &ps);
 	}
 
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglWinGlLeave(PuglView* view, bool drawing)
 {
 	if (drawing) {
@@ -265,16 +265,15 @@ puglWinGlLeave(PuglView* view, bool drawing)
 	}
 
 	wglMakeCurrent(NULL, NULL);
-
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglWinGlResize(PuglView* PUGL_UNUSED(view),
                 int       PUGL_UNUSED(width),
                 int       PUGL_UNUSED(height))
 {
-	return 0;
+	return PUGL_SUCCESS;
 }
 
 static void*
diff --git a/pugl/detail/x11.c b/pugl/detail/x11.c
index adf8c9d..429d89f 100644
--- a/pugl/detail/x11.c
+++ b/pugl/detail/x11.c
@@ -127,7 +127,8 @@ puglPollEvents(PuglWorld* world, const double timeout)
 		ret = select(nfds, &fds, NULL, NULL, &tv);
 	}
 
-	return ret < 0 ? PUGL_ERR_UNKNOWN : ret == 0 ? PUGL_FAILURE : PUGL_SUCCESS;
+	return ret < 0 ? PUGL_UNKNOWN_ERROR
+	               : ret == 0 ? PUGL_FAILURE : PUGL_SUCCESS;
 }
 
 static PuglView*
@@ -185,10 +186,13 @@ puglCreateWindow(PuglView* view, const char* title)
 	impl->screen  = DefaultScreen(display);
 
 	if (!view->backend || !view->backend->configure) {
-		return 1;
-	} else if (view->backend->configure(view) || !impl->vi) {
+		return PUGL_BAD_BACKEND;
+	}
+
+	PuglStatus st = view->backend->configure(view);
+	if (st || !impl->vi) {
 		view->backend->destroy(view);
-		return 2;
+		return st ? st : PUGL_BACKEND_FAILED;
 	}
 
 	Window xParent = view->parent ? (Window)view->parent
@@ -207,8 +211,8 @@ puglCreateWindow(PuglView* view, const char* title)
 		0, impl->vi->depth, InputOutput,
 		impl->vi->visual, CWColormap | CWEventMask, &attr);
 
-	if (view->backend->create(view)) {
-		return 3;
+	if ((st = view->backend->create(view))) {
+		return st;
 	}
 
 	XSizeHints sizeHints = getSizeHints(view);
@@ -239,7 +243,7 @@ puglCreateWindow(PuglView* view, const char* title)
 		fprintf(stderr, "warning: XCreateIC failed\n");
 	}
 
-	return 0;
+	return PUGL_SUCCESS;
 }
 
 PuglStatus
@@ -793,7 +797,7 @@ puglSetFrame(PuglView* view, const PuglRect frame)
 	    XMoveResizeWindow(view->world->impl->display, view->impl->win,
 	                      (int)frame.x, (int)frame.y,
 	                      (int)frame.width, (int)frame.height)) {
-		return PUGL_ERR_UNKNOWN;
+		return PUGL_UNKNOWN_ERROR;
 	}
 
 	return PUGL_SUCCESS;
diff --git a/pugl/detail/x11_cairo.c b/pugl/detail/x11_cairo.c
index 550144a..0753317 100644
--- a/pugl/detail/x11_cairo.c
+++ b/pugl/detail/x11_cairo.c
@@ -38,7 +38,7 @@ typedef struct  {
 	cairo_t*         frontCr;
 } PuglX11CairoSurface;
 
-static int
+static PuglStatus
 puglX11CairoConfigure(PuglView* view)
 {
 	PuglInternals* const impl = view->impl;
@@ -48,10 +48,10 @@ puglX11CairoConfigure(PuglView* view)
 	pat.screen = impl->screen;
 	impl->vi = XGetVisualInfo(impl->display, VisualScreenMask, &pat, &n);
 
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglX11CairoCreate(PuglView* view)
 {
 	PuglInternals* const impl    = view->impl;
@@ -77,16 +77,16 @@ puglX11CairoCreate(PuglView* view)
 		cairo_destroy(surface.backCr);
 		cairo_surface_destroy(surface.front);
 		cairo_surface_destroy(surface.back);
-		return PUGL_ERR_CREATE_CONTEXT;
+		return PUGL_CREATE_CONTEXT_FAILED;
 	}
 
 	impl->surface = calloc(1, sizeof(PuglX11CairoSurface));
 	*(PuglX11CairoSurface*)impl->surface = surface;
 
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglX11CairoDestroy(PuglView* view)
 {
 	PuglInternals* const       impl    = view->impl;
@@ -98,10 +98,10 @@ puglX11CairoDestroy(PuglView* view)
 	cairo_surface_destroy(surface->back);
 	free(surface);
 	impl->surface = NULL;
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglX11CairoEnter(PuglView* view, bool drawing)
 {
 	PuglInternals* const       impl    = view->impl;
@@ -111,10 +111,10 @@ puglX11CairoEnter(PuglView* view, bool drawing)
 		cairo_save(surface->frontCr);
 	}
 
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglX11CairoLeave(PuglView* view, bool drawing)
 {
 	PuglInternals* const       impl    = view->impl;
@@ -126,10 +126,10 @@ puglX11CairoLeave(PuglView* view, bool drawing)
 		cairo_restore(surface->frontCr);
 	}
 
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglX11CairoResize(PuglView* view, int width, int height)
 {
 	PuglInternals* const       impl    = view->impl;
@@ -141,13 +141,13 @@ puglX11CairoResize(PuglView* view, int width, int height)
 	cairo_surface_destroy(surface->front);
 	if (!(surface->front = cairo_surface_create_similar(
 		      surface->back, CAIRO_CONTENT_COLOR, width, height))) {
-		return PUGL_ERR_CREATE_CONTEXT;
+		return PUGL_CREATE_CONTEXT_FAILED;
 	}
 
 	surface->frontCr = cairo_create(surface->front);
 	cairo_save(surface->frontCr);
 
-	return 0;
+	return PUGL_SUCCESS;
 }
 
 static void*
diff --git a/pugl/detail/x11_gl.c b/pugl/detail/x11_gl.c
index b6f3c51..ea93de2 100644
--- a/pugl/detail/x11_gl.c
+++ b/pugl/detail/x11_gl.c
@@ -39,13 +39,13 @@ typedef struct {
 	int         double_buffered;
 } PuglX11GlSurface;
 
-static int
+static PuglStatus
 puglX11GlHintValue(const int value)
 {
 	return value == PUGL_DONT_CARE ? (int)GLX_DONT_CARE : value;
 }
 
-static int
+static PuglStatus
 puglX11GlGetAttrib(Display* const    display,
                    const GLXFBConfig fb_config,
                    const int         attrib)
@@ -55,7 +55,7 @@ puglX11GlGetAttrib(Display* const    display,
 	return value;
 }
 
-static int
+static PuglStatus
 puglX11GlConfigure(PuglView* view)
 {
 	PuglInternals* const impl    = view->impl;
@@ -86,7 +86,7 @@ puglX11GlConfigure(PuglView* view)
 	GLXFBConfig* fbc   = glXChooseFBConfig(display, screen, attrs, &n_fbc);
 	if (n_fbc <= 0) {
 		fprintf(stderr, "error: Failed to create GL context\n");
-		return 1;
+		return PUGL_CREATE_CONTEXT_FAILED;
 	}
 
 	surface->fb_config = fbc[0];
@@ -105,10 +105,10 @@ puglX11GlConfigure(PuglView* view)
 
 	XFree(fbc);
 
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglX11GlCreate(PuglView* view)
 {
 	PuglInternals* const    impl      = view->impl;
@@ -131,22 +131,25 @@ puglX11GlCreate(PuglView* view)
 		(CreateContextAttribs)glXGetProcAddress(
 			(const GLubyte*)"glXCreateContextAttribsARB");
 
-	impl->surface = surface;
-	surface->ctx  = create_context(display, fb_config, 0, GL_TRUE, ctx_attrs);
+	surface->ctx = create_context(display, fb_config, 0, GL_TRUE, ctx_attrs);
 	if (!surface->ctx) {
 		surface->ctx =
 			glXCreateNewContext(display, fb_config, GLX_RGBA_TYPE, 0, True);
 	}
 
+	if (!surface->ctx) {
+		return PUGL_CREATE_CONTEXT_FAILED;
+	}
+
 	glXGetConfig(impl->display,
 	             impl->vi,
 	             GLX_DOUBLEBUFFER,
 	             &surface->double_buffered);
 
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglX11GlDestroy(PuglView* view)
 {
 	PuglX11GlSurface* surface = (PuglX11GlSurface*)view->impl->surface;
@@ -155,18 +158,18 @@ puglX11GlDestroy(PuglView* view)
 		free(surface);
 		view->impl->surface = NULL;
 	}
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglX11GlEnter(PuglView* view, bool PUGL_UNUSED(drawing))
 {
 	PuglX11GlSurface* surface = (PuglX11GlSurface*)view->impl->surface;
 	glXMakeCurrent(view->impl->display, view->impl->win, surface->ctx);
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglX11GlLeave(PuglView* view, bool drawing)
 {
 	PuglX11GlSurface* surface = (PuglX11GlSurface*)view->impl->surface;
@@ -179,15 +182,15 @@ puglX11GlLeave(PuglView* view, bool drawing)
 
 	glXMakeCurrent(view->impl->display, None, NULL);
 
-	return 0;
+	return PUGL_SUCCESS;
 }
 
-static int
+static PuglStatus
 puglX11GlResize(PuglView* PUGL_UNUSED(view),
                 int       PUGL_UNUSED(width),
                 int       PUGL_UNUSED(height))
 {
-	return 0;
+	return PUGL_SUCCESS;
 }
 
 static void*
diff --git a/pugl/pugl.h b/pugl/pugl.h
index 580e9dc..067d780 100644
--- a/pugl/pugl.h
+++ b/pugl/pugl.h
@@ -80,13 +80,16 @@ typedef void* PuglHandle;
    Return status code.
 */
 typedef enum {
-	PUGL_SUCCESS,
-	PUGL_FAILURE,
-	PUGL_ERR_UNKNOWN,
-	PUGL_ERR_CREATE_WINDOW,
-	PUGL_ERR_SET_FORMAT,
-	PUGL_ERR_CREATE_CONTEXT,
-	PUGL_ERR_UNSUPPORTED_TYPE,
+	PUGL_SUCCESS,               /**< Success */
+	PUGL_FAILURE,               /**< Non-fatal failure */
+	PUGL_UNKNOWN_ERROR,         /**< Unknown system error */
+	PUGL_BAD_BACKEND,           /**< Invalid or missing backend */
+	PUGL_BACKEND_FAILED,        /**< Backend initialisation failed */
+	PUGL_REGISTRATION_FAILED,   /**< Window class registration failed */
+	PUGL_CREATE_WINDOW_FAILED,  /**< Window creation failed */
+	PUGL_SET_FORMAT_FAILED,     /**< Failed to set pixel format */
+	PUGL_CREATE_CONTEXT_FAILED, /**< Failed to create drawing context */
+	PUGL_UNSUPPORTED_TYPE,      /**< Unsupported data type */
 } PuglStatus;
 
 /**