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Re: Weirdness in comm(1)
Date: Sat, 28 Nov 2009 19:52:47 +0100
From: Joerg Sonnenberger <joerg%britannica.bec.de@localhost>
| getline behaves that way. The problem here is that comm needs to compare
| the two lines and the newline is not part of the logical line.
I understand the issue...
And no, getline() doesn't behave the way I described (which is not a
fault of getline() - just not doing the same thing).
What I meant was to remove the \n but return the length that included
the \n (if it was there) - that is, assuming it used getline() as the
lower level function, I'd do (with error/EOF checking omitted for simmplicity):
next_line(buf (and the rest))
size_t n = getline(buf,...);
if (buf[[n-1] == '\n')
buf[n-1] = 0;
Whether it uses getline(), fgets(), or while(getc()) as the
buffer filling function doesn't really matter for this
l1 = next_line(line1);
l2 = next_line(line2);
comp = compare(line1, line2);
if (comp == 0)
comp = l2 - l1;
/* now comp < 0 ==> line1 < line2, comp > 0 ==> line2 > line2
and comp == 0 ==> line1 == line2 */
That is, if it really is important that dealing with files containing
lines that don't contain the line terminating \n really is something worth
doing - I'm not sure it is, as I said last time, I'd just define the
behaviour in that case (and for files with embedded \0's, etc) as being
undefined - anything goes.
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