MESSAGE
| DATE | 2004-04-22 |
| FROM | Ruben Safir Secretary NYLXS
|
| SUBJECT | Re: [hangout] Debugging cdparanoia in C
|
Wonderful
Homework
I'm printing it out.
Ruben
On Thu, Apr 22, 2004 at 11:17:46AM -0400, Billy wrote:
> On Thu, Apr 22, 2004 at 06:15:04AM -0400, Ruben I Safir wrote:
> > ie: malloc in copystring.
> >
> > I don't know what was wrong with the standard strcpy program
>
> I'll assume you meant strdup.
>
> Their copystring function allocates 9 extra bytes to workaround
> what they claim is a bug in libc5 (details hazy).
>
> > Would you recommend using a signal handler for the malloc problem or
> > just exit. If you run out of ram, it might hang the program (and the
> > OS)
>
> Exit. The way they have it implemented, they're going
> to get to a signal handler (SIGSEGV) as soon as they try
> to copy characters into the null pointer. Portable
> code shouldn't rely on such local color as SIGSEGV, and should somehow
> exit or recover. Being careful about memory leaks goes a long way
> toward making sure it never comes to that, of course :) .
> I'm pretty sure there's plenty of error reporting/recovery
> infrastructure in cdparanoia, considering that paranoia's PRIMARY
> purpose is error recovery for CD audio..
>
> > In any event, for anyone following this thread, the malloc command in C allocates
> > a block of memory for future use, so properly writing an allocation should look something
> > like:
> >
> > char *p;
> >
> > if((p=malloc(1000))==NULL){
> > fprintf( STDERR, "%s", "Out of RAM - can not allocate more memory");
> > exit(0);
> > }
>
> Wrong.
>
> char *p;
> if((p=malloc(1000))==NULL){
> fprintf(stderr, "malloc failed: %s\n", strerror(errno));
> exit(1);
> }
> ...
> free(p);
>
> Find 5 differences between Ruben's version and my version.
--
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