Add function to set Py_NoSiteFlag global variable to 1 (pythonnet#971)

alexhelms · filmor · commit f2e6f6f89dde · 2019-10-23T09:32:44.000+01:00
* Add function to set Py_NoSiteFlag global variable to 1.
* Add myself to authors, update changelog.
diff --git a/AUTHORS.md b/AUTHORS.md
@@ -12,6 +12,7 @@
 
 ## Contributors
 
+-   Alex Helms ([@alexhelms](https://github.com/alexhelms))
 -   Alexandre Catarino([@AlexCatarino](https://github.com/AlexCatarino))
 -   Arvid JB ([@ArvidJB](https://github.com/ArvidJB))
 -   Benoît Hudson ([@benoithudson](https://github.com/benoithudson))
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -10,6 +10,7 @@ This document follows the conventions laid out in [Keep a CHANGELOG][].
 ### Added
 
 -   Added automatic NuGet package generation in appveyor and local builds
+-   Added function that sets Py_NoSiteFlag to 1.
 
 ### Changed
 
diff --git a/src/runtime/pythonengine.cs b/src/runtime/pythonengine.cs
@@ -130,6 +130,16 @@ public static string Compiler
             get { return Marshal.PtrToStringAnsi(Runtime.Py_GetCompiler()); }
         }
 
+        /// <summary>
+        /// Set the NoSiteFlag to disable loading the site module.
+        /// Must be called before Initialize.
+        /// https://docs.python.org/3/c-api/init.html#c.Py_NoSiteFlag
+        /// </summary>
+        public static void SetNoSiteFlag()
+        {
+            Runtime.SetNoSiteFlag();
+        }
+
         public static int RunSimpleString(string code)
         {
             return Runtime.PyRun_SimpleString(code);
diff --git a/src/runtime/runtime.cs b/src/runtime/runtime.cs
@@ -414,6 +414,8 @@ internal static int AtExit()
         internal static IntPtr PyNoneType;
         internal static IntPtr PyTypeType;
 
+        internal static IntPtr Py_NoSiteFlag;
+
 #if PYTHON3
         internal static IntPtr PyBytesType;
 #endif
@@ -1884,5 +1886,29 @@ internal static IntPtr PyMem_Realloc(IntPtr ptr, long size)
 
         [DllImport(_PythonDll, CallingConvention = CallingConvention.Cdecl)]
         internal static extern int Py_MakePendingCalls();
+
+        internal static void SetNoSiteFlag()
+        {
+            var loader = LibraryLoader.Get(OperatingSystem);
+
+            IntPtr dllLocal;
+            if (_PythonDll != "__Internal")
+            {
+                dllLocal = loader.Load(_PythonDll);
+            }
+
+            try
+            {
+                Py_NoSiteFlag = loader.GetFunction(dllLocal, "Py_NoSiteFlag");
+                Marshal.WriteInt32(Py_NoSiteFlag, 1);
+            }
+            finally
+            {
+                if (dllLocal != IntPtr.Zero)
+                {
+                    loader.Free(dllLocal);
+                }
+            }
+        }
     }
 }
