2.1.4.4 SetCommState

1 Description
2 Syntax
3 Parameters
4 Return
5 Examples
6 Remark
7 See Also
8 Header to Include
9 Reference

Description

The SetCommState function configures a communications device according to the specifications in a device-control block (a DCB structure). The function reinitializes all hardware and control settings, but it does not empty output or input queues.

Syntax

BOOL SetCommState( HANDLE hFile, LPDCB lpDCB )

Parameters

hFile: handle to the communications device.
lpDCB: Pointer to a DCB structure that contains the configuration information for the specified communications device.

Return

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero.

Examples

EX1

#include <mscomm.h>

BOOL Set_Comm_State()
{
	file ff;

	//Open comm port
	if (!ff.Open("COM1:",  file::modeReadWrite ))
	{
		ASSERT(FALSE);
		return FALSE;
	}

	UINT hCom = ff.GetHandle();

	if (hCom == file::hFileNull ) 
	{
		ASSERT(FALSE);
		return FALSE;
	}

	DCB dcb;

	if (!GetCommState((HANDLE)hCom, &dcb)) 
	{
		ASSERT(FALSE);
		return FALSE;
	}

	//dcb parameters for user
	dcb.BaudRate = CBR_9600;          // set the baud rate
	dcb.ByteSize = 8;               // data size, xmit, and rcv
	dcb.Parity = NOPARITY;            // no parity bit
	dcb.StopBits = ONESTOPBIT;        // one stop bit

	//dcb fixed parameters 
	dcb.fBinary=1; 
	dcb.fParity=0; 
	dcb.fOutxCtsFlow=0; 
	dcb.fOutxDsrFlow=0; 
	dcb.fDtrControl=0; 
	dcb.fDsrSensitivity=0; 

	dcb.fTXContinueOnXoff=0; 
	dcb.fRtsControl=0;

	if (!SetCommState((HANDLE)hCom, &dcb)) 
	{
		ASSERT(FALSE);
		return FALSE;
	}

	//...

	if( !ff.Close() ) // Close() function will happen automatically by the file class destructor.
	{
		ASSERT(FALSE);
		return FALSE;
	}
}