Method checkImageFileOpen

plugins/e57/libE57Format/src/ImageFileImpl.cpp:936–944

   }

   void ImageFileImpl::checkImageFileOpen( const char *srcFileName, int srcLineNumber,
                                           const char *srcFunctionName ) const
   {
      if ( !isOpen() )
      {
         throw E57Exception( ErrorImageFileNotOpen, "fileName=" + fileName(), srcFileName,
                             srcLineNumber, srcFunctionName );
      }
   }
}