Why my linux signal handler run only once
- by Henry Fané
#include <iostream>
#include <signal.h>
#include <fenv.h>
#include <string.h>
void signal_handler(int sig, siginfo_t *siginfo, void* context)
{
std::cout << " signal_handler " << fetestexcept(FE_ALL_EXCEPT) << std::endl;
throw "exception";
}
void divide() {
float a = 1000., b = 0., c, f = 1e-300;
c = a / b;
std::cout << c << " and f = " << f << std::endl;
}
void init_sig_hanlder() {
feenableexcept(FE_ALL_EXCEPT);
struct sigaction sa, initial_sa;
sa.sa_sigaction = &signal_handler ;
sigemptyset( &sa.sa_mask ) ;
sa.sa_flags = SA_SIGINFO; // man sigaction(3) // allows for void(*)(int,siginfo_t*,void*) handler
sigaction(SIGFPE, &sa, &initial_sa);
}
int main(int argc, char** argv) {
init_sig_hanlder();
while(true)
{
try {
sleep(1);
divide();
}
catch(const char * a) {
std::cout << "Exception in catch: " << a << std::endl;
}
catch(...) {
std::cout << "Exception in ..." << std::endl;
}
}
return 0;
}
Produce the following results on Linux/g++4.2:
signal_handler 0
Exception in catch: exception
inf and f = 0
inf and f = 0
inf and f = 0
inf and f = 0
So, signal handler is executed the first time but the next fp exception does not trigger the handler again. Where am I wrong ?
