Re: [PATCH 2/2] cyclictest: simplify rstat_setup

[Crystal Wood <crwood@redhat.com>]

On Tue, 2026-03-10 at 12:18 -0400, John Kacur wrote:
> 
> On Tue, 10 Mar 2026, Crystal Wood wrote:
> 
> > On Mon, 2026-03-09 at 18:55 -0400, John Kacur wrote:
> > > 
> > > On Sun, 1 Mar 2026, Lukas Beckmann wrote:
> > > > +static void rstat_setup(void)
> > > > +{
> > > > +	int fd;
> > > > +	pid_t pid;
> > > >  
> > > > -	if (mptr == (void*)-1)
> > > > -		fprintf(stderr, "ERROR: mmap, %s\n", strerror(errno));
> > > > +	pid = getpid();
> > > >  
> > > > -	return mptr;
> > > > -}
> > > > +	snprintf(shm_name, SHM_BUF_SIZE, "%s%d", "/cyclictest", pid);
> > > >  
> > > > -static int rstat_mlock(void *mptr)
> > > > -{
> > > > -	int err;
> > > 
> > > errno = 0 before the call to shm_unlink for good defensive programming
> > > other than that the patch looks good, I will do a little more testing
> > 
> > Defensive against the library returning -1 without setting errno?  Seems
> > a bit paranoid and cluttery... all for the payoff of an "ERROR:
> > shm_unlink Success" message if it ever does happen *and* the old errno
> > happened to be ENOENT.
> > 
> > And the current code uses it even in places that print the message
> > regardless.
> > 
> > -Crystal
> > 
> > 
> 
> Isn't that what defensive programming is? Guarding against something that 
> is unlikely? It's one line of code that I requested in a patch that gets 
> rid of many lines of code, is that really worth arguing over?

Eh, it wasn't so much an argument over this patch, as a "we're supposed
to do *what* before each library call?" reflex.

-Crystal