#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <errno.h>

#define BASIC_UNIT	1024*1024
//#define BASIC_UNIT	1
char large_buf[BASIC_UNIT];

void fd_pair(int *fd)
{
/*	if(pipe(fd)<0)
		perror("pipe"); */
	if(socketpair(AF_UNIX,SOCK_STREAM,0,fd) <0)
		perror("socketpair");
}

void set_nonblocking(int fd)
{
	int val=fcntl(fd,F_GETFL);
	if(val==-1)
		perror("fcntl");
	val|=O_NONBLOCK;
	fcntl(fd,F_SETFL,val);
}

int main(int argc,char *argv[])
{
	int fd[2],rc;
	fd_pair(fd);
	  
	set_nonblocking(fd[1]);

	while(1){
		rc=write(fd[1],large_buf,sizeof(large_buf));
		if(rc<0){
			if(errno==EWOULDBLOCK)
				printf("blocking, thank you, goodbye.\n");
			else
				perror("write");

			break;
		}
	}

	return 0;
}