issue #0002891: Sketching impossible, Type.Error Exception

src/Gui/Application.cpp

@@ -1483,6 +1483,14 @@ void Application::runApplication(void)
     // http://forum.freecadweb.org/viewtopic.php?f=3&t=15540
     mainApp.setAttribute(Qt::AA_DontShowIconsInMenus, false);
 
+#ifdef Q_OS_UNIX
+    // Make sure that we use '.' as decimal point. See also
+    // http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=559846
+    // and issue #0002891
+    // http://doc.qt.io/qt-5/qcoreapplication.html#locale-settings
+    setlocale(LC_NUMERIC, "C");
+#endif
+
     // check if a single or multiple instances can run
     it = cfg.find("SingleInstance");
     if (it != cfg.end() && mainApp.isRunning()) {

src/Main/MainGui.cpp

@@ -98,16 +98,11 @@ int main( int argc, char ** argv )
     QFile::setEncodingFunction(myEncoderFunc);
     QFile::setDecodingFunction(myDecoderFunc);
 #endif
-    // Make sure that we use '.' as decimal point. See also
-    // http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=559846
-    putenv("LC_NUMERIC=C");
     putenv("PYTHONPATH=");
 #elif defined(FC_OS_MACOSX)
     (void)QLocale::system();
-    putenv("LC_NUMERIC=C");
     putenv("PYTHONPATH=");
 #else
-    setlocale(LC_NUMERIC, "C");
     _putenv("PYTHONPATH=");
     // https://forum.freecadweb.org/viewtopic.php?f=4&t=18288
     // https://forum.freecadweb.org/viewtopic.php?f=3&t=20515