open打开\创建一个文件，进行写读操作（7.13）

open

#include<stdio.h>
#include <unistd.h>
#include <fcntl.h>
 int main()
{
	int fd = open("./d.txt", O_RDWR | O_CREAT, 0666);
	if(fd < 0)
	{
		perror("open");
	}
	
	printf("fd = %d\n", fd);
	close(fd);
	return 0;

}

write

#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <string.h>
 int main()
{
	int fd = open("./d.txt", O_RDWR | O_CREAT, 0666);
	if(fd < 0)
	{
		perror("open");
	}
	
	printf("fd = %d\n", fd);
	char msg[128] = "正在写文件～";
	write(fd, msg, strlen(msg));
	
	close(fd);
	return 0;

}

read

#include<stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include<sys/types.h>
#include <string.h>
 int main()
{
	int fd = open("./d.txt", O_RDWR | O_CREAT, 0666);
	if(fd < 0)
	{
		perror("open");
	}
	
	printf("fd = %d\n", fd);
	
	char msg[128] = "";
	read(fd, msg, sizeof(msg));//此时文件中已经有之前写过的字符存在了，所以可以直接读取
	puts(msg);

	close(fd);
	return 0;

}

执行结果在word文档中

标签：7.13,int,写读,fd,printf,msg,include,open
来源： https://blog.csdn.net/HanLongXia/article/details/118708798