CreateFile WriteFile ReadFile FlushFileBuffers的基本用法

#include <Windows.h>

int _tmain(int argc, _TCHAR* argv[])
{
	HANDLE hFile;
	hFile = CreateFile("E://Test.txt",
		GENERIC_READ,
		FILE_SHARE_READ,
		NULL,
		OPEN_EXISTING,
		FILE_ATTRIBUTE_NORMAL,
		NULL);
	
	if (hFile == INVALID_HANDLE_VALUE)
	{
		printf("Invalid handle when read file create/n");
		return -1;
	}

	char buffer[256] = {0};
	DWORD readBytes = 0;
	BOOL flag = ReadFile(hFile, buffer, 256, &readBytes, NULL);
	if (flag == FALSE)
	{
		printf("ReadFile failed/n");
		return -1;
	}

	printf("Read bytes = %d/n", readBytes);

	printf("Read content = %s/n", buffer);

	CloseHandle(hFile);

	printf("****************************/n/n");

	hFile = CreateFile("E://Test.txt",
		GENERIC_WRITE | GENERIC_READ,
		FILE_SHARE_READ,
		NULL,
		OPEN_EXISTING,
		FILE_ATTRIBUTE_NORMAL,
		NULL);
	if (hFile == INVALID_HANDLE_VALUE)
	{
		printf("Invalid handle/n");
		return -1;
	}

	char outBuffer[256] = "/r/nwhat a fucking day!";

	long distance = 0;
	DWORD retVal = 0;
	retVal = SetFilePointer(hFile, 0, NULL, FILE_END);
	if (retVal == 0xFFFFFFFF)
	{
		retVal = GetLastError();
		printf("LastError = %d/n", retVal);
		CloseHandle(hFile);

		return -1;
	}

	DWORD outBytes = 0;
	flag = WriteFile(hFile, outBuffer, strlen(outBuffer), &outBytes, NULL);
	if (flag == FALSE)
	{
		printf("Write file failed/n");
		return -1;
	}

	if (0 == FlushFileBuffers(hFile))  //如果WriteFile执行成功，这里就不需要调用
	{
		printf("Flush failed/n");
	}

	retVal = SetFilePointer(hFile, 0, NULL, FILE_BEGIN);
	if (retVal == 0xFFFFFFFF)
	{
		retVal = GetLastError();
		printf("LastError = %d/n", retVal);
		CloseHandle(hFile);

		return -1;
	}

	char readBuffer[256] = {0};
	flag = ReadFile(hFile, readBuffer, 256, &readBytes, NULL);
	if (flag == FALSE)
	{
		printf("ReadFile failed/n");
		return -1;
	}
	printf("readBuffer = %s/n", readBuffer);

	CloseHandle(hFile);

	return 0;
}