On Jul 9 11:16, Brian Inglis wrote: > On 2018-07-09 10:49, Corinna Vinschen wrote: > > On Jul 9 15:47, Lavrentiev, Anton (NIH/NLM/NCBI) [C] wrote: > >> Hello, > >> > >> the following sample coredumps with FPE at localhost.cc:1962 with the latest snapshot (6/29/2018): > ... > > You can simplify your testcase by not calling any time functions: > > > > #define _GNU_SOURCE > > #include > > #include > > #include > > > > #define SECSPERDAY 86400 > > > > int main(int argc, char **argv) > > { > > feenableexcept(FE_ALL_EXCEPT); > > long tdays = argc > 1 ? strtol (argv[1], NULL, 10) : 189; > > long seconds = tdays * SECSPERDAY + 0.5; > > printf ("%ld\n", seconds); > > } > > > > This generates a SIGFPE on Linux as well. > > > > The line computing seconds is the same line as used by the localtime > > function. Cygwin shares the entire localtime code with the various > > BSDs, so I guess they would have the same problem. > What is that line meant to do? Am I missing something? > It should be the equivalent of (tdays*SECSPERDAY*2 + 1)/2! > It converts an integer value to double, adds 1/2, and throws it away on > conversion back, unless the intermediate has insufficient mantissa bits, in > which case, it loses the low bits? You may want to ask the original author why he used FP arithmetic in this place. Maybe it's a way to avoid integer overflow. I'm reluctant to change this given that this code is still used in BSD as well. > > Bottom line is, don't bulk enable FP exceptions, but only if you really > > need it for certain parts of your code. Don't expect library functions > > to be SIGFPE clean under all circumstances. > > Maybe selectively enable specific FPEs to check for where needed. > Or be careful what you wish for, as you just might get a lot more than you > bargained for ;^> That's what I meant. Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Maintainer cygwin AT cygwin DOT com Red Hat