fifo2.c

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>

#define FIFO_NAME "/tmp/my_fifo"

int main(int argc, char *argv[])
{
	int res;
	int open_mode =0;
	int i;

	if (argc<2)
	{
		fprintf(stderr,"Usage:%s <some combination of O_RDONLY O_WRONLY O_NONBLOCK>\n",*argv);
		exit(EXIT_FAILURE);
	}


	for(i=1;i<argc;i++)
	{
		if(strncmp(*++argv,"O_RDONLY",8)==0)
			open_mode |= O_RDONLY;
		if(strncmp(*argv,"O_WRONLY",8)==0)
			open_mode |=O_WRONLY;
		if(strncmp(*argv,"O_NONBLOCK",10)==0)
			open_mode |= O_NONBLOCK;
	}

	if(access(FIFO_NAME,F_OK)==-1)
	{
		res=mkfifo(FIFO_NAME,0777);
		if(res!=0)
		{
			fprintf(stderr,"Could not create fifo %s\n",FIFO_NAME);
			exit(EXIT_FAILURE);
		}
	}

	printf("Process %d opening FIFO\n",getpid(),res);
	res=open(FIFO_NAME,open_mode);
	printf("Process %d result %d\n",getpid(),res);
	sleep(5);
	if(res !=-1) (void)close(res);
	printf("Process %d finished\n",getpid());
	exit(EXIT_SUCCESS);

}