Ian, I don't know about "guaranteed," but it certainly looks like the htonl/bswap macros intend to avoid double-evaluating macro parameters.
On Fri, Apr 14, 2017 at 8:53 AM, Ian Lepore <i...@freebsd.org> wrote: > On Fri, 2017-04-14 at 08:32 -0700, Conrad Meyer wrote: >> On Fri, Apr 14, 2017 at 4:58 AM, Andrey V. Elsukov <a...@freebsd.org> >> wrote: >> > >> > Author: ae >> > Date: Fri Apr 14 11:58:41 2017 >> > New Revision: 316826 >> > URL: https://svnweb.freebsd.org/changeset/base/316826 >> > >> > Log: >> > Avoid undefined behavior. >> > >> > The 'pktid' variable is modified while being used twice between >> > sequence points, probably due to htonl() is macro. >> FYI — there are a ton of similar reports in sys/rpc due to the XDR >> macros (which read a network value off a pointer and increment it). >> See e.g., IXDR_GET_UINT32() macro. >> >> Best, >> Conrad > > Aren't they all false positives, since the macros involved are g'teed > not to evaluate their arguments more than once as written (because > __builtin_constant_p always evaluates at compile time)? Do we really > want to churn our source code to eliminate false positives from some > tool that appears to still be in its alpha-testing state? > > -- Ian _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
