On Sat, 2022-11-26 at 17:47 +0000, Jonathan Wakely wrote: > On Sat, 26 Nov 2022, 15:48 Gavin Ray, <ray.gavi...@gmail.com> wrote: > > > I was using if (fd != -1) and was still getting the warning which > > confused > > me > > My suggestion was maybe to add the exact condition the fd analyzer > > is > > looking for to the warning so that folks know how to fix it/trigger > > its 'true' branch. > > > > e.g. instead of: > > "fd may not be valid" > > > > Something like this, or thereabouts: > > "fd may not be valid (expecting fd >= 0)" > > > > That seems like an analyzer bug, checking for -1 should be ok. POSIX > is > clear that open and socket return -1 on error. I didn't check all the > other > functions that return new file descriptors, but I think they're the > same.
Looking at sm-fd.cc: fd_state_machine::on_condition it looks like the analyzer handles both checks against -1 (eq/ne) *and* checks for >= 0, so maybe the .dot file needs updating. Gavin, if you have a reproducer in C [1] where the wording of the message seems "off", please can you file it in bugzilla and I'll take a look next week. The fd state machine is new in GCC 13, so it's interesting to get this into the hands of end-users. Thanks Dave [1] Sadly, C++ in -fanalyzer is sufficiently broken right now that it's not worth filing extra bugs on top of the ones I already know about, alas.
