ungetc() exists for exactly this application. But when you want more abstract input stream than FILE* you have to reimplement that yourself on higher layer. Iro

ungetc() exists for exactly this application. But when you want more abstract input stream than FILE* you have to reimplement that yourself on higher layer. Ironically even libc implementation needs an more generic abstraction to implement scanf() and sscanf() (ie. you either have two separate implementations of these or don't internally use ungetc())