/*
    signal.c
    
    Started by Jeff Ondich on 3/26/96
    Last modified 4/1/02
    
    This program gives a simple example of how a process
    can catch a signal.  Here, SIGINT signals (typically
    generated by the user hitting CTL-C) are caught.
*/

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

const int limit = 2000000000;
const int frequency = 50000000;

void interrupt_handler( int );

int main()
{
    long        i;

    printf( "Hi, I'm %d\n", getpid() );

    /* The initial handler for the SIGINT signal is
       assuredly the default, so confusion will not reign */

    if( signal( SIGINT, interrupt_handler ) != SIG_DFL )
        fprintf( stderr, "I'm confused.\n" );


    /* Start counting. */

    for( i=0; i < limit; i++ )
    {
        if( i % frequency == 0 )
        {
            fprintf( stderr, "%ld\n", i );
            fflush( stderr );
        }
    }

    return 0;
}


void interrupt_handler( int sig )
{
    fprintf( stderr, "Sorry, but I just don't want to quit.\n" );
    fflush( stderr );
    (void)signal( SIGINT, interrupt_handler );
}