fifo_write.c

工ARM＿LINUX的几个源代码

/*fifo_write.c*/
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <fcntl.h>
#include FIFO "/tmp/myfifo"

main(int argc,char** argv)
/*参数为即将写入的字节数*/
{
		char w_buf[100];
		int fd;
		int nwrite;
		if(fd == -1)
			if(errno == ENXIO)
				printf("open error:no reading process\n");

/*打开FIFO管道，并设置非阻塞标志*/
 
	fd=open(FIFO,O_WRONLY|O_NONBLOCK,0);
		if(argc == 1)
		printf("Please send something\n");
	strcpy(w_buf,argv[1]);//拷贝字符串，将参数argv[1]字符串拷贝至参数w_buf所指的地址.
/*向管道中写入字符串*/
	if((nwrite=write(fd,w_buf,100))==-1)
	{
		if(errno == EAGAIN)
			printf("The FIFO has not been read yet.Please try later\n");
	}
	else 
			printf("write %s to the FIFO\n",w_buf);
	}
		exit(1);
	}
	while(1)
	{
		memset(buf_r,0,sizeof(buf_r));
		if((nread = read (fd,buf_r,100)) == -1){
			if(errno == EAGAIN)
				printf("no data yet\n");
			}
			printf("read %s from FIFO\n",buf_r);
			sleep(1);
		}
		pause();
		unlink(FIFO);
	}