I would like to make the definition of an URL user friendly using compiler directives, so only the parameters mus be entered:
#define OPEN_WEATHER_MAP_APP_ID "208085abb5a3859d1e32341d6e1f9079"
#define OPEN_WEATHER_MAP_LOCATION_ID "2928810"
#define OPEN_WEATHER_MAP_LANGUAGE "de"
#define OPEN_WEATHER_MAP_UNITS "metric"
#define OPEN_WEATHER_MAP_URL "http://api.openweathermap.org/data/2.5/weather?id=" ## OPEN_WEATHER_MAP_LOCATION_ID ## "&units=" ## OPEN_WEATHER_MAP_UNITS ## "&appid=" ## OPEN_WEATHER_MAP_APP_ID ## "&lang=" ## OPEN_WEATHER_MAP_LANGUAGE
but the concatenation does not succeed:
pasting ""http://api.openweathermap.org/data/2.5/weather?id="" and "OPEN_WEATHER_MAP_LOCATION_ID" does not give a valid preprocessing token
What did I make wrong?
Thank you...