From 59dd9296a70771ac141571516938bd9b3303d179 Mon Sep 17 00:00:00 2001
From: TSR Berry <20988865+TSRBerry@users.noreply.github.com>
Date: Sun, 4 Jun 2023 04:19:00 +0200
Subject: [PATCH] Add GetErrorText and reply codes

---
 SPB/Platform/X11/X11.cs | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/SPB/Platform/X11/X11.cs b/SPB/Platform/X11/X11.cs
index 7f712ab..a965616 100644
--- a/SPB/Platform/X11/X11.cs
+++ b/SPB/Platform/X11/X11.cs
@@ -120,7 +120,7 @@ public enum XEventName
         [StructLayout(LayoutKind.Sequential)]
         public struct XErrorEvent
         {
-            public XEventName type;
+            public XReplyCode type;
             public Display display;
             public IntPtr resourceid;
             public IntPtr serial;
@@ -131,6 +131,14 @@ public struct XErrorEvent
 
         public delegate int XErrorHandler(Display displayHandle, ref XErrorEvent errorEvent);
 
+        public enum XReplyCode : byte
+        {
+            // Normal reply
+            X_Reply = 1,
+            // Error
+            X_Error = 0
+        }
+
         public enum XRequest : byte
         {
             X_CreateWindow = 1,
@@ -258,6 +266,9 @@ public enum XRequest : byte
         [DllImport(LibraryName, EntryPoint = "XSetErrorHandler")]
         public extern static IntPtr SetErrorHandler(XErrorHandler error_handler);
 
+        [DllImport(LibraryName, EntryPoint = "XGetErrorText", CharSet = CharSet.Unicode)]
+        public extern static int GetErrorText(Display display, int code, IntPtr buffer, int length);
+
         public enum Gravity
         {
             ForgetGravity = 0,
@@ -337,7 +348,22 @@ public struct XSetWindowAttributes
 
         static int ErrorHandler(Display displayHandle, ref XErrorEvent errorEvent)
         {
-            Console.WriteLine($"XError: {errorEvent.type} result is {errorEvent.error_code}");
+            IntPtr buffer = Marshal.AllocHGlobal(256);
+            string error;
+            int result = GetErrorText(displayHandle, errorEvent.error_code, buffer, 256);
+
+            if (result == 0)
+            {
+                error = Marshal.PtrToStringAuto(buffer);
+            }
+            else
+            {
+                error = $"GetErrorText returned: {result}";
+            }
+
+            Marshal.FreeHGlobal(buffer);
+
+            Console.WriteLine($"XError: {errorEvent.type} result is {error} (code: {errorEvent.error_code})");
             Console.Out.Flush();
             return 0;
         }