Why is my linux signal handler working only once

Question

#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;
}

Print 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, the signal handler is executed for the first time, but the next fp exception does not call the handler again. Where am I mistaken?

Answer 1

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Answer 2

, "extern" C ", / ​​ C, ++ . , " C ", , , , " "

, Linux reset , .

Answer 3

sigsetjmp/siglongjmp , .

, jmp ( , ++ ).

, , SIGFPE fe * except().

: ? , , feclearexcept() , SIGFPE, .