add the ability to add an exception handler in the raise function

Author: thelfer

src/Raise.cxx

@@ -0,0 +1,25 @@
+/*!
+ * \file   src/Raise.cxx
+ * \brief    
+ * \author Thomas Helfer
+ * \date   02/04/2021
+ */
+
+#include "MGIS/Raise.hxx"
+
+namespace mgis {
+
+  static ExceptionHandler& getInternalExceptionHandler() {
+    static ExceptionHandler h = nullptr;
+    return h;
+  }  // end of getInternalExceptionHandlerPointer
+
+  void setExceptionHandler(ExceptionHandler h) {
+    getInternalExceptionHandler() = h;
+  }  // end of setExceptionHandler
+
+  ExceptionHandler getExceptionHandler() {
+    return getInternalExceptionHandler();
+  }  // end of getExceptionHandler
+
+} // end of namespace mgis