diff --git a/CMakeLists.txt b/CMakeLists.txt
index ab13656b5ba..093ca10fd28 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -751,8 +751,8 @@ endif()
 set (AGGRESSIVE_SAFE_MODE FALSE CACHE BOOL "Forces a aggressive safe mode where issues like unsafe thread access will resort in fatal exceptions")
 
 if(MSVC)
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /utf-8 /std:c++17")
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /utf-8 /std:c++17")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /utf-8 /std:c++17 /permissive-")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /utf-8 /std:c++17 /permissive-")
   set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO}")
   set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG}")
   # disable macros that offend std::numeric_limits<T>::min()/max()
diff --git a/src/providers/wfs/qgscachedirectorymanager.cpp b/src/providers/wfs/qgscachedirectorymanager.cpp
index a5004a8070c..1c134a9779a 100644
--- a/src/providers/wfs/qgscachedirectorymanager.cpp
+++ b/src/providers/wfs/qgscachedirectorymanager.cpp
@@ -26,7 +26,7 @@
 #include <QTimer>
 #include <QDateTime>
 
-#if !defined(Q_OS_ANDROID)
+#if not defined( Q_OS_ANDROID )
 #include <QSharedMemory>
 #endif
 
@@ -82,7 +82,7 @@ QString QgsCacheDirectoryManager::getCacheDirectory( bool createIfNotExisting )
       QgsDebugMsgLevel( QStringLiteral( "Creating our cache dir %1/%2" ).arg( baseDirectory, processPath ), 2 );
       QDir( baseDirectory ).mkpath( processPath );
     }
-#if !defined(Q_OS_ANDROID)
+#if not defined( Q_OS_ANDROID )
     if ( mCounter == 0 && mKeepAliveWorks )
     {
       mThread = new QgsCacheDirectoryManagerKeepAlive( createAndAttachSHM() );
@@ -159,7 +159,7 @@ bool QgsCacheDirectoryManager::removeDir( const QString &dirName )
   return dir.rmdir( dirName );
 }
 
-#if !defined(Q_OS_ANDROID)
+#if not defined( Q_OS_ANDROID )
 std::unique_ptr<QSharedMemory> QgsCacheDirectoryManager::createAndAttachSHM()
 {
   std::unique_ptr<QSharedMemory> sharedMemory;
@@ -189,7 +189,7 @@ std::unique_ptr<QSharedMemory> QgsCacheDirectoryManager::createAndAttachSHM()
 
 void QgsCacheDirectoryManager::init()
 {
-#if !defined(Q_OS_ANDROID)
+#if not defined( Q_OS_ANDROID )
   auto sharedMemory = createAndAttachSHM();
   mKeepAliveWorks = sharedMemory.get() != nullptr;
   sharedMemory.reset();
@@ -225,7 +225,7 @@ void QgsCacheDirectoryManager::init()
         {
           canDelete = true;
         }
-#if !defined(Q_OS_ANDROID)
+#if not defined( Q_OS_ANDROID )
         else if ( mKeepAliveWorks )
         {
           canDelete = true;
@@ -290,7 +290,7 @@ void QgsCacheDirectoryManager::init()
 
 // -------------------------
 
-#if !defined(Q_OS_ANDROID)
+#if not defined( Q_OS_ANDROID )
 // We use a keep alive mechanism where every KEEP_ALIVE_DELAY ms we update
 // a shared memory segment with the current timestamp. This way, other QGIS
 // processes can check if the temporary directories of other process correspond
diff --git a/src/providers/wfs/qgscachedirectorymanager.h b/src/providers/wfs/qgscachedirectorymanager.h
index b19317f9538..c43ed18a52d 100644
--- a/src/providers/wfs/qgscachedirectorymanager.h
+++ b/src/providers/wfs/qgscachedirectorymanager.h
@@ -1,5 +1,5 @@
 /***************************************************************************
-    qgsbackgroundcachedshareddata.h
+    qgsbacckgroundcachedshareddata.h
     ---------------------
     begin                : October 2019
     copyright            : (C) 2016-2019 by Even Rouault
@@ -20,7 +20,7 @@
 #include <QThread>
 #include <QMutex>
 
-#if !defined(Q_OS_ANDROID)
+#if not defined( Q_OS_ANDROID )
 #include <QSharedMemory>
 #endif
 
@@ -59,7 +59,7 @@ class QgsCacheDirectoryManager
     //! Called by constructor
     void init();
 
-#if !defined(Q_OS_ANDROID)
+#if not defined( Q_OS_ANDROID )
     //! Create a shared memory segment for the keep-alive mechanism
     std::unique_ptr<QSharedMemory> createAndAttachSHM();
 #endif
@@ -73,7 +73,7 @@ class QgsCacheDirectoryManager
     static bool removeDir( const QString &dirName );
 };
 
-#if !defined(Q_OS_ANDROID)
+#if not defined( Q_OS_ANDROID )
 //! For internal use of QgsCacheDirectoryManager
 class QgsCacheDirectoryManagerKeepAlive: public QThread
 {