If you are certain that there are only two words then it is fairly simple:
char str[20] = "SINGLE\0*DOUBLE*";
char* first = str;
char* second = first + strlen(first) + 1;
printf("First: %s, Second: %s\n", first, second);
If you expect multiple entries then it is a good idea to terminate the final entry with an extra null character:
char list[] = "first\0second\0third\0\0"