Serial Communication C++ Select Connect - c++

Question

main
#include "stdafx.h"
#include <iostream>
#include "SerialPort.h"
#include <WinBase.h>
using namespace std;
int main()
{
cout << "Monitoring System \n";
cout << "Please select a connection method\n\n";
cout << "1.Serial 2.TCP \n";
int num;
while (!(cin >> num))
{
cin.clear();
cin.ignore(INT_MAX, '\n');
cout << "Please enter a number only ";
}
if(num==1)
{
int i,SN;
int k=0;
cout << "Scan all ports that are currently...\n";
for (i = 1; i < 30; ++i)
{
if (COM_exists(i))
{
cout <<++k<< ".COM" << i << "\n";
}
}
cout << "\nselect a port to connect.\n";
scanf_s("%d", &SN, sizeof SN);
if (SN == 1)
{
SerialPort PortOpen("COM", CBR_115200, 8, "#or", 24);
PortOpen.getData();
PortOpen.getData();
cout << PortOpen.SerialBuffer << endl;
return 0;
}
}
}
serial cpp
#include "stdafx.h"
#include <string.h>
#include "SerialPort.h"
using namespace std;
BOOL COM_exists(int port)
{
char buffer[7];
COMMCONFIG CommConfig;
DWORD size;
if (!(1 <= port && port <= 30))
{
return FALSE;
}
snprintf(buffer, sizeof buffer, "COM%d", port);
size = sizeof CommConfig;
// COM port exists if GetDefaultCommConfig returns TRUE
// or changes <size> to indicate COMMCONFIG buffer too small.
return (GetDefaultCommConfig(buffer, &CommConfig, &size)
|| size > sizeof CommConfig);
}
SerialPort::SerialPort(LPCSTR COM,int setBaudRate, int setByteSize, char* commandBuffer, int BufSize) {
this->BufSize = BufSize;
this->SerialBuffer = new char[BufSize];
this->NoBytesRead = BufSize;
Connect(COM, setBaudRate, setByteSize, commandBuffer);
}
void SerialPort::Connect(LPCSTR COM ,int setBaudRate, int setByteSize, char* commandBuffer) {
this->COMport = COM;
this->hComm = CreateFile(COM, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL); // (port name, read/write , no sharing , no security, open existing port only, non overlapped i/o , null for comm devices)
if (this->hComm == INVALID_HANDLE_VALUE)
cout << "PortOpen Fail." << endl;
else {
cout << "PortOpen Success." << endl;
sendCommand(setBaudRate, setByteSize, commandBuffer);
}
}
void SerialPort::sendCommand(int setBaudRate, int setByteSize, char* commandBuffer) {
this->commandBuffer = commandBuffer;
this->dNoOFBytestoWrite = sizeof(commandBuffer);
this->Status = WriteFile(hComm, commandBuffer, dNoOFBytestoWrite, &dNoOfBytesWritten, NULL);
DCB dcbSerialParams = { 0 };
dcbSerialParams.DCBlength = sizeof(dcbSerialParams);
dcbSerialParams.BaudRate = setBaudRate;
dcbSerialParams.ByteSize = setByteSize;
dcbSerialParams.StopBits = ONESTOPBIT;
dcbSerialParams.Parity = NOPARITY;
COMMTIMEOUTS timeouts = { 0 };
timeouts.ReadIntervalTimeout = 10;
timeouts.ReadTotalTimeoutConstant = 10;
timeouts.ReadTotalTimeoutMultiplier = 10;
timeouts.WriteTotalTimeoutConstant = 50;
timeouts.WriteTotalTimeoutMultiplier = 10;
if (this->Status)
cout << "Command Successful" << endl;
else
{
cout << "fail to Command" << endl;
}
}
void SerialPort::getData() {
ReadFile(this->hComm, &*this->SerialBuffer, this->BufSize, &this->NoBytesRead, NULL);
}
SerialPort.h
#pragma once
#include <windows.h>
#include <iostream>
#include <stdlib.h>
#include <WinBase.h>
using namespace std;
class SerialPort {
public:
HANDLE hComm;
LPCSTR COMport;
DWORD dNoOFBytestoWrite;
DWORD dNoOfBytesWritten;
int BufSize;
int Status;
char* SerialBuffer;
char* commandBuffer;
DWORD NoBytesRead;
int port;
SerialPort(LPCSTR COMport,int setBaudRate, int setByteSize, char* commandBuffer, int BufSize);
void Connect(LPCSTR COMport, int setBaudRate, int setByteSize, char* commandBuffer);
void sendCommand(int setBaudRate, int setByteSize, char* commandBuffer);
void getData();
};
BOOL COM_exists(int port);
I am writing a code to connect by selecting a serial port.
example, 1.COM1 / 2.COM3 / 3.COM4
How do I modify the main to connect COM4 that matches No. 3?
How do I automatically read and use matching ports to match numbers?
I am writing a code to connect by selecting a serial port.
example, 1.COM1 / 2.COM3 / 3.COM4
How do I modify the main to connect COM4 that matches No. 3?
How do I automatically read and use matching ports to match numbers?

Answer 1

I would personally never ever use the old school style open and close COM port to detect if it exists.
Assuming you are running on Windows I would use the SetupDi to find the serial port without opening it.
A little snippet to adapt:
#include <initguid.h>
#include <windows.h> // Data Type
#include <setupapi.h> // ::SetupDi*********
#include <devguid.h> // Device
// Global Variables
HDEVINFO m_hDevInfo; //!< Reference to device information set
SP_DEVINFO_DATA m_spDevInfoData; //!< Device information structure (references a device instance that is a member of a device information set)
BOOL m_bDevInfo; //!< Tested to ensure EnumDeviceInfo has been called
short m_MemberIndex = -1; //!< Preserves state between EnumDeviceInfo calls
bool WIN_EnumDeviceInfo ()
{
m_MemberIndex++;
m_spDevInfoData.cbSize = sizeof(SP_DEVINFO_DATA);
m_bDevInfo = ::SetupDiEnumDeviceInfo(m_hDevInfo, m_MemberIndex, &m_spDevInfoData);
return m_bDevInfo;
}
bool WIN_GetDeviceRegistryProperty(DWORD Property, PBYTE PropertyBuffer)
{
BOOL bGotRegProp = ::SetupDiGetDeviceRegistryProperty(m_hDevInfo, &m_spDevInfoData,
Property,
0L,
PropertyBuffer,
2048,
0);
return bGotRegProp;
}
void ScanSerial()
{
WORD Flags;
PCWSTR Enumerator=0;
const GUID *ClassGuid;
HWND m_hWnd;
ClassGuid = &GUID_DEVCLASS_PORTS;
Flags = DIGCF_PROFILE;
m_hDevInfo = SetupDiGetClassDevs(ClassGuid, Enumerator, m_hWnd, Flags);
while(WIN_EnumDeviceInfo())
{
wchar_t szBuf[MAX_PATH] = {0};
if(WIN_GetDeviceRegistryProperty(SPDRP_CLASS, (PBYTE)szBuf))
{
wchar_t szFriendlyName[MAX_PATH] = {0};
WIN_GetDeviceRegistryProperty (SPDRP_FRIENDLYNAME, (PBYTE)szFriendlyName);
}
}
}
From the szFriendlyName you can filter the COMx number without opening it or either confusing them...
Try and enjoy...