pythonnet
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -47,6 +47,7 @@ This document follows the conventions laid out in [Keep a CHANGELOG][].
 -   Fixed wrong version number in `conda.recipe` (#398)
 -   Fixed fixture location for Python tests and `Embedded_Tests`
 -   Fixed `PythonException` crash during Shutdown (#400)
+-   Fixed `Py_Main` & `PySys_SetArgvEx` no mem error on `UCS4/PY3` (#399)
 
 ### Removed
 

diff --git a/src/embed_tests/pyinitialize.cs b/src/embed_tests/pyinitialize.cs
@@ -33,11 +33,6 @@ public static void LoadDefaultArgs()
         [Test]
         public static void LoadSpecificArgs()
         {
-            if (Environment.GetEnvironmentVariable("TRAVIS") == "true" &&
-                Environment.GetEnvironmentVariable("TRAVIS_PYTHON_VERSION") != "2.7")
-            {
-                Assert.Ignore("FIXME: Fails on Travis/PY3+: Fatal Python error: no mem for sys.argv");
-            }
             var args = new[] { "test1", "test2" };
             using (new PythonEngine(args))
             using (var argv = new PyList(Runtime.Runtime.PySys_GetObject("argv")))

diff --git a/src/runtime/runtime.cs b/src/runtime/runtime.cs
@@ -667,8 +667,41 @@ internal unsafe static extern IntPtr
         public unsafe static extern int
             Py_Main(
                 int argc,
-                [MarshalAs(UnmanagedType.LPArray, ArraySubType = UnmanagedType.LPWStr)] string[] argv
+                IntPtr lplpargv
             );
+
+        public static int Py_Main(int argc, string[] argv)
+        {
+            // Totally ignoring argc.
+            argc = argv.Length;
+
+            var allStringsLength = 0;
+            foreach (string x in argv)
+            {
+                allStringsLength += x.Length + 1;
+            }
+            int requiredSize = IntPtr.Size * argc + allStringsLength * UCS;
+            IntPtr mem = Marshal.AllocHGlobal(requiredSize);
+            try
+            {
+                // Preparing array of pointers to UTF32 strings.
+                IntPtr curStrPtr = mem + argc * IntPtr.Size;
+                for (var i = 0; i < argv.Length; i++)
+                {
+                    // Unicode or UTF8 work
+                    Encoding enc = UCS == 2 ? Encoding.Unicode : Encoding.UTF32;
+                    byte[] zstr = enc.GetBytes(argv[i] + "\0");
+                    Marshal.Copy(zstr, 0, curStrPtr, zstr.Length);
+                    Marshal.WriteIntPtr(mem + IntPtr.Size * i, curStrPtr);
+                    curStrPtr += zstr.Length;
+                }
+                return Py_Main(argc, mem);
+            }
+            finally
+            {
+                Marshal.FreeHGlobal(mem);
+            }
+        }
 #elif PYTHON2
         [DllImport(Runtime.dll, CallingConvention = CallingConvention.Cdecl,
             ExactSpelling = true, CharSet = CharSet.Ansi)]
@@ -2087,9 +2120,41 @@ internal unsafe static extern IntPtr
         internal unsafe static extern void
             PySys_SetArgvEx(
                 int argc,
-                [MarshalAs(UnmanagedType.LPArray, ArraySubType = UnmanagedType.LPWStr)] string[] argv,
+                IntPtr lplpargv,
                 int updatepath
             );
+
+        internal static void PySys_SetArgvEx(int argc, string[] argv, int updatepath)
+        {
+            // Totally ignoring argc.
+            argc = argv.Length;
+
+            var allStringsLength = 0;
+            foreach (string x in argv)
+            {
+                allStringsLength += x.Length + 1;
+            }
+            int requiredSize = IntPtr.Size * argc + allStringsLength * UCS;
+            IntPtr mem = Marshal.AllocHGlobal(requiredSize);
+            try
+            {
+                // Preparing array of pointers to UTF32 strings.
+                IntPtr curStrPtr = mem + argc * IntPtr.Size;
+                for (var i = 0; i < argv.Length; i++)
+                {
+                    Encoding enc = UCS == 2 ? Encoding.Unicode : Encoding.UTF32;
+                    byte[] zstr = enc.GetBytes(argv[i] + "\0");
+                    Marshal.Copy(zstr, 0, curStrPtr, zstr.Length);
+                    Marshal.WriteIntPtr(mem + IntPtr.Size * i, curStrPtr);
+                    curStrPtr += zstr.Length;
+                }
+                PySys_SetArgvEx(argc, mem, updatepath);
+            }
+            finally
+            {
+                Marshal.FreeHGlobal(mem);
+            }
+        }
 #elif PYTHON2
         [DllImport(Runtime.dll, CallingConvention = CallingConvention.Cdecl,
             ExactSpelling = true, CharSet = CharSet.Ansi)]