Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!gatech!ncsuvx!mcnc!duke!bet
From: bet@orion.mc.duke.edu (Bennett Todd)
Newsgroups: comp.lang.c
Subject: Re: best way to return (char *)
Message-ID: <14944@duke.cs.duke.edu>
Date: 12 Jul 89 06:15:31 GMT
References: <7800013@gistdev> <2793@solo8.cs.vu.nl> <1989Jun23.124149.1374@twwells.com>
Sender: news@duke.cs.duke.edu
Reply-To: bet@orion.mc.duke.edu (Bennett Todd)
Organization: Diagnostic Physics, Radiology, DUMC
Lines: 27
In-reply-to: bill@twwells.com (T. William Wells)

As has been said, in general the best mechanism to use depends on other
features of the problem at hand. Here's a specific solution that I liked
for a particular problem.

I wanted to be able to easily loop along line at a time through a file,
without having to worry about maximum line lengths. So I wrote a routine
getline(3b):

	char *getline(char *, FILE *);

which might be used like this:

	char *line = NULL;
	...
	while (line = getline(line, fp)) {
		/* process the line */
	}

getline(3b) allocates the line buffer if it is passed in NULL for a
buffer pointer; on EOF it frees the buffer and returns NULL. It actually
malloc's a 2^n byte long buffer, stores n in the first element, and the
string starting in the second element, and returns a pointer to the
second element. That way it knows the length, and can realloc as
necessary to avoid overfilling the buffer.

-Bennett
bet@orion.mc.duke.edu