1、利用多线程与有名管道技术，实现两个进程之间发送即时消息，实现聊天功能。

fifo1源文件

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

void* readfifo()
{
	const char *sfifoname = "fifo1";

	int fd = open(sfifoname, O_RDONLY);
	if (fd == -1)
	{
		printf("open %s failed, %s\n", sfifoname, strerror(errno));
		return NULL;
	}

	int len = 0;
	char buf[128];

	while (1)
	{
		memset(buf, 0, sizeof(buf));
		len = read(fd, buf, sizeof(buf));
		if (len > 0)
		{
			printf("%s\n", buf);
		}
		else
		{
			break;
		}
	}
	close(fd);
	return NULL;
}

void* writefifo()
{
	const char *sfifoname = "fifo2";

	int fd = open(sfifoname, O_WRONLY);
	if (fd == -1)
	{
		printf("open %s failed, %s\n", sfifoname, strerror(errno));
		return NULL;
	}
	char buf[128];
	while (1)
	{
		memset(buf, 0, sizeof(buf));
		read(STDIN_FILENO, buf, sizeof(buf));
		write(fd, buf, sizeof(buf));
	}
	close(fd);
	return NULL;
}


int main(int arg, char *args[])
{
	pthread_t thr_d1, thr_d2;
	pthread_create(&thr_d1, NULL, readfifo, NULL);
	pthread_create(&thr_d2, NULL, writefifo, NULL);
	pthread_join(thr_d1, NULL);//主线程挂起，等待thr_d1退出
	pthread_join(thr_d1, NULL);//主线程挂起，等待thr_d2退出
	return 0;
}

fifo源文件

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

void* readfifo()
{
	const char *sfifoname = "fifo2";

	int fd = open(sfifoname, O_RDONLY);
	if (fd == -1)
	{
		printf("open %s failed, %s\n", sfifoname, strerror(errno));
		return NULL;
	}

	int len = 0;
	char buf[128];

	while (1)
	{
		memset(buf, 0, sizeof(buf));
		len = read(fd, buf, sizeof(buf));
		if (len > 0)
		{
			printf("%s\n", buf);
		}
		else
		{
			break;
		}
	}
	close(fd);
	return NULL;
}

void* writefifo()
{
	const char *sfifoname = "fifo1";

	int fd = open(sfifoname, O_WRONLY);
	if (fd == -1)
	{
		printf("open %s failed, %s\n", sfifoname, strerror(errno));
		return NULL;
	}
	char buf[128];
	while (1)
	{
		memset(buf, 0, sizeof(buf));
		read(STDIN_FILENO, buf, sizeof(buf));
		write(fd, buf, sizeof(buf));
	}
	close(fd);
	return NULL;
}


int main(int arg, char *args[])
{
	pthread_t thr_d1, thr_d2;
	pthread_create(&thr_d1, NULL, readfifo, NULL);
	pthread_create(&thr_d2, NULL, writefifo, NULL);
	pthread_join(thr_d1, NULL);
	pthread_join(thr_d2, NULL);
	return 0;
}

makefile一定要注意添加-lpthread

.SUFFIXES: .c .o

CC=gcc
ASRCS=myfifo1.c			
BSRCS=myfifo2.c
	
AOBJS=$(ASRCS:.c=.o)
BOBJS=$(BSRCS:.c=.o)

AEXEC=myfifo1
BEXEC=myfifo2

all:$(AOBJS) $(BOBJS)
	$(CC) -o $(AEXEC) $(AOBJS) -lpthread
	$(CC) -o $(BEXEC) $(BOBJS) -lpthread
	@echo '-------------ok--------------'

.c.o:
	$(CC) -Wall -g -o $@ -c $< 

clean:
	rm -f $(AOBJS)
	rm -f $(BOBJS)
	rm -f core*