Eric Blake wrote: > Do we want to offer ftello(fp) as the shorter alternative to > lseek(fileno(fp),0,SEEK_CUR) for testing seekability?
I don't think we can guarantee that, if we stick to the abstractions laid out by POSIX. The ftello.html page says "The ftell() function shall obtain the current value of the file-position indicator for the stream pointed to by stream." So clearly it talks about a property of the stream. I can see two situations when ftello() would succeed although lseek() would always fail: - A stream with an infinite-size buffer (a buffer growing as needed), - An input stream that keeps track of the current position simply by counting the number of bytes read so far - assuming no fflush() call occurs. Bruno