Using fseek to backtrack

Question

Is using fseek to backtrack character fscanf operations reliable?

Like for example if I have just fscanf-ed 10 characters but

Answer 1

Just tried this with VS2008 and found that fscanf and fseek treated the CR and LF characters in the same way (as a single character).

So with two files:

0000000: 3132 3334 3554 3738 3930 3132 3334 3536 12345X7890123456

and

0000000: 3132 3334 350d 0a37 3839 3031 3233 3435 12345..789012345

If I read 15 characters I get to the second '5', then seek back 10 characters, my next character read is the 'X' in the first case and the CRLF in the second.

This seems like a very OS/compiler specific problem.