【Linux篇】fwrite函数

#include <stdio.h>
#include <string.h>
//fwrite函数
int main()
{
	FILE *fp = NULL;
	int nRet = 0;
	char readBuff[12];
	char *writeBuff = "Hello World";
	memset(readBuff,0,12);

	fp = fopen("mm","r+");//打开文件“mm”,可读可写
       if(fp == NULL)//判断文件是否打开
       {
       		printf("open failed!\n");
		return -1;
       }
	printf("open success!\n");

	nRet = fread(readBuff,4,2,fp);//每个元素4个字节，读取两个元素
	if(nRet <= 0)//判断是否读取数据成功
	{
		printf("fread failed!\n");
		return -3;
	}
	printf("fread %s\n",readBuff);

	nRet = fwrite(writeBuff,4,1,fp);//每次写4个字节，只写一次
	if(nRet <= 0)//判断是否写入数据成功
	{
		printf("fwrite failed!\n");
	
	}

	nRet  = fclose(fp);
	if(nRet)//判断文件是否关闭
	{
		printf("close failed!\n");
		return -2;
	}
	printf("close success!\n");

	return 0;
}