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FPE_FLTSUB where FLT_FLTINV is expected
- From: "Lavrentiev, Anton (NIH/NLM/NCBI) [C]" <lavr at ncbi dot nlm dot nih dot gov>
- To: "cygwin at cygwin dot com" <cygwin at cygwin dot com>
- Date: Mon, 25 Jun 2018 20:51:53 +0000
- Subject: FPE_FLTSUB where FLT_FLTINV is expected
Hello,
The following code produces FPE_FLTSUB(22) for the signal code whereas all platforms (Linux, Mac, FreeBSD) where I tested it, consistently yield FPE_FLTINV
(which on CYGWIN has a value of 21):
#define _GNU_SOURCE
#include <fenv.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
void sigfpe(int signo, siginfo_t* si, void* ucontext)
{
printf("code = %d\n", si->si_code);
_exit(255);
}
int main()
{
double a = 0, b = 0;
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sa.sa_sigaction = sigfpe;
sa.sa_flags = SA_SIGINFO;
sigaction(SIGFPE, &sa, 0);
feenableexcept(FE_ALL_EXCEPT);
printf("%lf", a / b);
return 0;
}
I suppose that this block of code in exceptions.cc is not particularly correct, and only the last case (STACK_CHECK) actually pertains to the FLTSUB situation,
while all previous labels should be redirected to FPE_FLTINV (which, BTW, seems not being used at all in CYGWIN):
case STATUS_FLOAT_DENORMAL_OPERAND:
case STATUS_FLOAT_DIVIDE_BY_ZERO:
case STATUS_FLOAT_INVALID_OPERATION:
case STATUS_FLOAT_STACK_CHECK:
si.si_signo = SIGFPE;
si.si_code = FPE_FLTSUB;
break;
Thanks for looking into this!
Regards,
Anton Lavrentiev
Contractor NIH/NLM/NCBI
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