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Message-ID: <030901c50e1d$51a22b30$e6ec6f83@robinson.cam.ac.uk>
From: "Max Bowsher" <maxb AT ukf DOT net>
To: <cygwin AT cygwin DOT com>
Subject: Problem with alarm() not functioning twice in one program.
Date: Tue, 8 Feb 2005 20:29:33 -0000
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The following program produces the output:

Begin
Done
Begin
...and then hangs.

Can anyone help me understand why?

Thankyou,
Max.



#include <stdio.h>
#include <signal.h>
#include <setjmp.h>
#include <unistd.h>

jmp_buf timer;

void alarm_handler(int dummy)
{
  longjmp(timer, 1);
}

void speedtest(void)
{
  fprintf(stderr, "Begin\n");
  signal(SIGALRM, alarm_handler);

  if (setjmp(timer) == 0) {
    alarm(1);
    while(1) {};
  }

  signal(SIGALRM, SIG_DFL);
  fprintf(stderr, "Done\n");
  return;
}

int main(int argc, char* argv[])
{
  speedtest();
  speedtest();

  return 0;
}


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