Available COM ports scan

**Buzzer** · 05-11-2006

Hi, I am fairly new in C/C++ programming.
I want to scan available com ports 1-99.

This ugly method works, anyone having a
better propose?

CreateFile(pcCommPort, etc...
does not accept that pcCommPort is a string.

I am using dev-cpp

Code:

char* pcCommPort;
char portnbr;

for (portnbr = 1; portnbr <=99; portnbr++) {
  // 1..7
   if (portnbr == 8) { pcCommPort = "\\\\.\\COM8"; }
   if (portnbr == 9) { pcCommPort = "\\\\.\\COM9"; }
   if (portnbr == 10) { pcCommPort = "\\\\.\\COM10"; }
   if (portnbr == 11) { pcCommPort = "\\\\.\\COM11"; }
  // 12..99

hComm = CreateFile(pcCommPort,
                      GENERIC_READ | GENERIC_WRITE,
                      0,    // comm devices must be opened w/exclusive-access
                      NULL, // no security attributes
                      OPEN_EXISTING, // comm devices must use OPEN_EXISTING
                      0,    // non overlapped I/O
                      NULL  // hTemplate must be NULL for comm devices
                      );

**Bench82** · 05-11-2006

if you need to pass a C string to a function, then the C++ string has the c_str() function:

Code:

#include <string>
#include <iostream>
// ...
std::string s("hello, world");
std::cout << s.c_str();

Then you can use the C++ way to concatenate strings with other types..

Code:

#include <sstream>
#include <string>
#include <iostream>

int main()
{
    int num(10);
    std::stringstream ss;
    ss << "Hello, World  " << num;
    std::string foo;
    std::getline(ss, foo);
    std::cout << foo.c_str();
}

**Shakti** · 05-11-2006

look into strings and stringstreams to see how you can append the value in portnbr to the pcCommPort. Bascly what you want is to have pcCommPort contain "\\\\.\\COM" at first and then you just append the value in portnbr to that, and thats your final string

**Buzzer** · 05-11-2006

Hmm I try but still have the same problem.
I get compiler error:

cannot convert `std::string' to `const CHAR*' for argument `1' to `void* CreateFileA(const CHAR*, DWORD, DWORD, _SECURITY_ATTRIBUTES*, DWORD, DWORD, void*)'

Asking humble for help

**Shakti** · 05-11-2006

need to use c_str() like this:
std::string yourString;
SomeFuncThatRequresCharPointer(yourString.c_str()) ;

**Buzzer** · 05-12-2006

Ok TY ALL!

Finally with some help I solved it

here is the solution

Code:

for (int i=1; i<99; i++) {
    stringstream ss;
    ss << "\\\\.\\COM" << i;
    

   hComm = CreateFile(ss.str().c_str(), .........etc

Thread: Available COM ports scan

Thread Tools

Search Thread

Display

Available COM ports scan

:(

I solved it!

Similar Threads

virtual ports

Control of ports

while (scan != 'y' or 'n) or if(scan != 'y' or 'n)

Controlling ports

Who will map the scan code (inserted by VKD_Force_keys) to virtual key code?