what does C/C++ handler SIGFPE?
c++, sigfpe, signals
Solution
This is interesting: With the `fprintf` commented out, the compiler has determined that the calculated result: `d = b/c` is an unused local expression and can be optimized away.
Clearly though, it is not side-effect free in its execution, but the compiler can't determine anything about the runtime environment at this stage. I'm surprised that static analysis doesn't pick this up as a warning (at least) in a modern compiler.
@vonbrand is right. You got lucky with what you're doing in the (asynchronous) signal handler.
Edit: when you say "signal_handler keeps calling", do you mean it's repeating indefinitely? If so, there could be issues with underlying system calls restarting. Try: `siginterrupt(SIGFPE, 1);` (assuming it's available).
Problem
well, I have searched the articles about SIGFPE ,then I wrote a few tests but it's behavoir is strange. Then I have to post it here to ask for help. Is the GCC/G++ or ISO C++ clearly defined what happens if divide by zero? 1) I searched the article : Division by zero does not throw SIGFPE it sames the output is inf 2) If I rewrite it as the following: ``` void signal_handler (int signo) { if(signo == SIGFPE) { std::cout << "Caught FPE\n"; } } int main (void) { signal(SIGFPE,(*signal_handler)); int b = 1; int c = 0; int d = b/c; //fprintf(stderr,"d number is %d\n,d); return 0; } ``` then signal_handler will not happens. but if I uncomment the line ``` //fprintf(stderr,"d number is %d\n,d); ``` then signal_handler keeps calling. can someone explains it ?