Linux文件编程demo4文件读取操作.c

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

int main()
{
	int fd;
	char *buf = "longhaiyanghenshuai";
	fd = open("./file1",O_RDWR);
	if(fd = -1){
		printf("open failed\n");
		fd = open("./file1",O_RDWR|O_CREAT,0600);
		if(fd > 0 ){
			printf("creat successful\n");
		}
		
		
		
	}
	int n_write = write(fd,buf,strlen(buf));
	if(n_write != -1){
		printf("write successful\n");
	}
	close(fd);//对文件写操作 写完光标在内容尾部，关闭文件重新打开让光标到内容头部
	fd = open("./file1",O_RDWR);
	char *readbuf = (char *)malloc(sizeof(char)*n_write+1);
	int n_read = read(fd,readbuf,n_write);
    printf("read = %d,context:%s\n",n_read,readbuf);
	
	close(fd);
	
	
	
}```