Re: (int)sizeof in smtpd
On Thu, May 08, 2014 at 18:43, Alexandre Ratchov wrote: > On Thu, May 08, 2014 at 12:35:56PM -0400, Ted Unangst wrote: >> This is wrong in several ways. >> >> Never cast sizeof down, always cast the comparison variable up. >> >> I'll specifically call out this change: >> >> -if (snprintf(buf, sizeof(buf)) >= (int)sizeof(buf)) >> +if ((size_t)snprintf(buf, sizeof(buf)) >= sizeof(buf)) >> > > note that the >= operator promotes int to size_t, which makes the > cast useless and could permit lines to be shortened. Yes, I did that first, but somebody added -Wsign-compare to the Makefile. Silencing that warning is the root of a lot of evil. The cure is usually worse than the disease.
Re: (int)sizeof in smtpd
On 08 May 2014, at 18:43, Alexandre Ratchov wrote: > On Thu, May 08, 2014 at 12:35:56PM -0400, Ted Unangst wrote: >> This is wrong in several ways. >> >> Never cast sizeof down, always cast the comparison variable up. >> >> I'll specifically call out this change: >> >> -if (snprintf(buf, sizeof(buf)) >= (int)sizeof(buf)) >> +if ((size_t)snprintf(buf, sizeof(buf)) >= sizeof(buf)) >> > > note that the >= operator promotes int to size_t, which makes the > cast useless and could permit lines to be shortened. Wouldn't that produce a signed vs. unsigned comparison?
Re: (int)sizeof in smtpd
On Thu, May 08, 2014 at 12:35:56PM -0400, Ted Unangst wrote: > This is wrong in several ways. > > Never cast sizeof down, always cast the comparison variable up. > > I'll specifically call out this change: > > - if (snprintf(buf, sizeof(buf)) >= (int)sizeof(buf)) > + if ((size_t)snprintf(buf, sizeof(buf)) >= sizeof(buf)) > note that the >= operator promotes int to size_t, which makes the cast useless and could permit lines to be shortened.
