char *curl_escape( const char *url, int length );
This function will convert the given input string to an URL encoded string and return that as a new allocated string. All input characters that are not a-z, A-Z or 0-9 will be converted to their "URL escaped" version (%NN where NN is a two-digit hexadecimal number).
If the 'length' argument is set to 0, curl_escape() will use strlen() on the input 'url' string to find out the size.
You must curl_free(3) the returned string when you're done with it.