open函数使用基础

#include <stdio.h>
#include <string.h>

#define MAX_SIZE 1024*8

int main()
{
	int len, n, file_len;
	char buf[MAX_SIZE] = {0};
	char *ptr = NULL;
	FILE* fp = NULL;
	char file_name[] = {"/record/hd01/qh00013.dat"};

	fp = fopen(file_name, "r+");
	if(NULL == fp)
	{
		printf("fopen fail\n");
		return -1;
	}

	len = sizeof(buf);
	printf("TTT----len[%d]-----\n", len);
	ptr = buf;	
	n   = len;
	while(0 < n)
	{
		memcpy(ptr, "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", 32);
		ptr += 32;
		n   -= 32;
	}
	

	file_len = 0;
	fseek(fp, 0, SEEK_SET);
	while(1)
	{
		//if(0 != feof(fp))
		if(file_len > 500*1024*1024)
		{
			fseek(fp, 0, SEEK_SET);
		}
		
		n = fwrite(buf, 1, len, fp);
		usleep(10*1000);
		printf("TTT------return[%d]----len[%d]---\n", n, len);
	}
	
	return 0;
}