//-------------------------------------------------------------------
//	racedemo.cpp
//
//	This program shows the effects of a "race condition" which
//	can result when more than one process attempts to access a 
//	common resource -- in this case, the stdout stream.  It is
//	adapted from an example by W. Richard Stevens in "Advanced 
//	Programming in the UNIX Environment" (1993).
//
//	programmer: ALLAN CRUSE
//	written on: 10 OCT 2004
//-------------------------------------------------------------------

#include <stdio.h>	// for perror(), setbuf(), putc() 
#include <unistd.h>	// for fork() 
#include <stdlib.h>	// for exit() 

#define DELAY_COUNT 20000000

void one_character_at_a_time( char *msg )
{
	setbuf( stdout, NULL );		// set to 'unbuffered'
	while ( int c = *msg++ )
		{
		putc( c, stdout );
		int	i = DELAY_COUNT;
		while( --i );
		}
}	


int main( void )
{
	int	pid = fork();

	if ( pid < 0 ) { perror( "fork" ); exit(1); }
	else if ( pid == 0 )
		{
		one_character_at_a_time( "output from child process \n" );
		}
	else	{
		one_character_at_a_time( "output from parent process \n" );
		}
	exit(0);
}