Re: the purpose of dynamic memory allocation

[jhutz+ () cmu edu (Jeffrey Hutzelman)]

> Along the same lines, I've seen the following occur:
>
> while(bytes = recv(sock, buf, bufsize, 0))
>         write(fd, buf, bytes);
>
> Normally, recv fails with a 0, but if things go wrong, it will fail with a
> -1.  The third argument to write is UNSIGNED.  If that occurs, we'll start
> at the addr of buf, and attempt to write 4GB to the fd.  This is just one
> example of why I do not consider signed-unsigned mismatch warnings to be
> inconsequential.

recv returns the number of bytes received, or -1 if there is an error.
The only way it can return 0 is if a 0-byte message is received
(e.g. a 0-length UDP packet).  While I'll agree that complaints about
size and signed-ness mismatches are a Good Thing, the above code
suffers from the (IMHO) much worse problem of failing to check for
an error return from recv....

-- Jeffrey T. Hutzelman (N3NHS) <jhutz+ () cmu edu>
   Systems Programmer
   School of Computer Science - Research Computing Facility
   Carnegie Mellon University - Pittsburgh, PA