Simplify error creation

Author: BCSharp

Src/IronPython.Modules/_overlapped.cs

@@ -5,11 +5,14 @@
 using System;
 using System.Numerics;
 using System.Runtime.InteropServices;
+using System.Runtime.Versioning;
 
 using IronPython.Runtime;
 
 [assembly: PythonModule("_overlapped", typeof(IronPython.Modules.PythonOverlapped), PlatformsAttribute.PlatformFamily.Windows)]
 namespace IronPython.Modules {
+
+    [SupportedOSPlatform("windows")]
     public static class PythonOverlapped {
         public const int ERROR_NETNAME_DELETED = 64;
         public const int ERROR_SEM_TIMEOUT = 121;

Src/IronPython.Modules/_winapi.cs

@@ -9,16 +9,19 @@
 using System;
 using System.Numerics;
 using System.Runtime.InteropServices;
+using System.Runtime.Versioning;
 using System.Text;
 
 using IronPython.Runtime;
 using IronPython.Runtime.Operations;
 
 [assembly: PythonModule("_winapi", typeof(IronPython.Modules.PythonWinApi), PlatformsAttribute.PlatformFamily.Windows)]
 namespace IronPython.Modules {
+    [SupportedOSPlatform("windows")]
     public static class PythonWinApi {
         #region Public API
 
+        [SupportedOSPlatform("windows")]
         public static object? ConnectNamedPipe(BigInteger handle, bool overlapped = false) {
             if (overlapped) throw new NotImplementedException();
 

Src/IronPython.Modules/nt.cs

@@ -2318,8 +2318,13 @@ private static Exception GetOsError(int error, string? filename = null, string?
 
 #if FEATURE_NATIVE || FEATURE_CTYPES
 
+        [SupportedOSPlatform("windows")]
+        internal static Exception GetLastWin32Error(string? filename = null, string? filename2 = null)
+            => GetWin32Error(Marshal.GetLastWin32Error(), filename, filename2);
+
         // Gets an error message for a Win32 error code.
-        internal static string GetMessage(int errorCode) {
+        [SupportedOSPlatform("windows")]
+        private static string GetWin32ErrorMessage(int errorCode) {
             string msg = new Win32Exception(errorCode).Message;
             // error codes: https://docs.microsoft.com/en-us/windows/win32/debug/system-error-codes
             if (errorCode is not (< 0 or >= 8200 or 34 or 106 or 317 or 718)) {
@@ -2332,11 +2337,9 @@ internal static string GetMessage(int errorCode) {
             return msg.TrimEnd('\r', '\n', '.');
         }
 
-        internal static Exception GetLastWin32Error(string? filename = null, string? filename2 = null)
-            => GetWin32Error(Marshal.GetLastWin32Error(), filename, filename2);
-
+        [SupportedOSPlatform("windows")]
         private static Exception GetWin32Error(int error, string? filename = null, string? filename2 = null) {
-            var msg = GetMessage(error);
+            var msg = GetWin32ErrorMessage(error);
             return PythonOps.OSError(0, msg, filename, error, filename2);
         }
 

Src/IronPython.Modules/posix.cs

@@ -6,6 +6,7 @@
 
 using System;
 using System.IO;
+using System.Runtime.InteropServices;
 using System.Runtime.Versioning;
 using System.Text;
 
@@ -28,7 +29,8 @@ public static partial class PythonNT {
         [SupportedOSPlatform("linux")]
         [SupportedOSPlatform("osx")]
         private static Exception GetLastUnixError(string? filename = null, string? filename2 = null)
-            => GetOsError(NativeConvert.FromErrno(Syscall.GetLastError()), filename, filename2);
+            // On POSIX, GetLastWin32Error returns the errno value, same as GetLastPInvokeError
+            => GetOsError(Marshal.GetLastWin32Error(), filename, filename2);
 
 
         [SupportedOSPlatform("linux")]
@@ -41,7 +43,7 @@ private static int strerror_r(int code, StringBuilder buffer)
         [SupportedOSPlatform("linux")]
         [SupportedOSPlatform("osx")]
         private static Tuple<int, Stream, int, Stream> CreatePipeStreamsUnix() {
-            Mono.Unix.UnixPipes pipes = Mono.Unix.UnixPipes.CreatePipes();
+            UnixPipes pipes = UnixPipes.CreatePipes();
             return Tuple.Create<int, Stream, int, Stream>(pipes.Reading.Handle, pipes.Reading, pipes.Writing.Handle, pipes.Writing);
         }
 #endif
@@ -169,7 +171,7 @@ internal static void ftruncateUnix(int fd, long length) {
             Errno errno;
             do {
                 result = Syscall.ftruncate(fd, length);
-            } while (Mono.Unix.UnixMarshal.ShouldRetrySyscall(result, out errno));
+            } while (UnixMarshal.ShouldRetrySyscall(result, out errno));
 
             if (errno != 0)
                 throw GetOsError(NativeConvert.FromErrno(errno));