VC并口读写

VC并口读写

int OpenLPT()
{
if ((hdlPrinter = CreateFile("LPT1", GENERIC_READ | GENERIC_WRITE,
0, NULL, CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL,
NULL )) == (HANDLE) -1 )
{
return -1 ;
}
return 0;
}

int CloseLPT ()
{
if (hdlPrinter != (HANDLE) -1) {
CloseHandle(hdlPrinter);
hdlPrinter = (HANDLE)-1;
return 0;
}
else
return -1;
}

int WriteLPT(char * chCmd, int nLenCmd)
{
BOOL rWriteFile;
DWORD dwByteWritten;
DWORD DelayTime, BeginTime;
OVERLAPPED Write_OS;
//memset(&Write_OS, 0, sizeof(OVERLAPPED));
DelayTime = 30000;
BeginTime = GetTickCount();

do{

OpenLPT();
rWriteFile = WriteFile(hdlPrinter, chCmd, nLenCmd, &dwByteWritten, NULL);
/**********
if(FlushFileBuffers(hdlPrinter) == FALSE)
{

}

*************/
/*******************************************/
CloseLPT();
LogFileWrite(chCmd,nLenCmd);
if  (rWriteFile != 0)
return 0;
else
return -1;
}while((GetTickCount()-BeginTime) <DelayTime);
return -1;
}