gistfile1.cpp

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

char pathname[] = "channel.fifo.out";
int file=0;

bool is_equal(char * str1, char * str2, int length){
	for(int i = 0; i<length ; ++i){
		if(str1[i] != str2[i])
			return false;
	}
	return true;
}

void * thread1(void * fake){
	char write_str[8] = "thread1";
	char read_str[8];
	size_t size;
	usleep(1);
	while(1){
		size = write(file, write_str, 8);
		if(!size){
			printf("Write error1\n");
		}
		size = read(file, read_str, 8);
		read_str[7]=0;
		if(size!=8){
			printf("Read error1\n");
		}
		else {
			printf("from thread2: %s\n", read_str);
		}
	}
}

void * thread2(void * fake){
	char write_str[8] = "thread2";
	char read_str[8];
	size_t size;
	while(1){
		size = write(file, write_str, 8);
		if(!size){
			printf("Write error2\n");
		}
		size = read(file, read_str, 8);
		read_str[7]=0;
		if(size!=8){
			printf("Read error2\n");
		}
		else{
			printf("from thread1: %s\n", read_str);
		}
	}
	
}

pthread_t create1(){
	pthread_t thid;
	int result;
	int *fakenum = NULL;
	result = pthread_create(&thid, (pthread_attr_t *)NULL, thread1, NULL);
	if(result != 0) {
		printf("Error on thread create, return value = %d\n", result);
		exit(-1);
	}
	return thid;
}

pthread_t create2(){
	pthread_t thid;
	int result;
	int *fakenum = NULL;
	result = pthread_create(&thid, (pthread_attr_t *)NULL, thread2, NULL);
	if(result != 0) {
		printf("Error on thread create, return value = %d\n", result);
		exit(-1);
	}
	return thid;
}

int main(){
	
	if(mkfifo(pathname, O_RDWR | 0666) < 0){
		printf("Error creating fifo!\nError: %s\n", strerror(errno));
		exit(-1);
	}
	if((file = open(pathname, O_RDWR)) < 0){
		printf("Error creating file!\nError: %s\n", strerror(errno));
		exit(-1);
	}
	pthread_t thid1 = create1();
	pthread_t thid2 = create2();
	
	pthread_join(thid1, (void **)NULL);
	pthread_join(thid2, (void **)NULL);
	
	return 0;
}