Variables global to a single request need special treatment as some server APIs may run several PHP requests in different threads at the same time. Request global variables are declared using the %<global>% tag and its %name% and %type% attributes. Simple default values can be given with the %value% attribute, else you can always initialize request globals within the %RINIT% internal function. To access your request global variables you have to use the the %EXTNAME_G% macro (replace %EXTNAME% with the uppercased name of your extension).