How do I get a list of available serial ports in Win32?

Question

I have some legacy code that provides a list of the available COM ports on the PC by calling the EnumPorts() function and then filtering for the port names that start with \

Answer 1

you can make loop for example from 1 to 50 and try to open each port. If the port is available, the open will work. If the port is in use, you'll get a sharing error. If the port is not installed, you'll get a file not found error.

to open the port use CreateFile API:

HANDLE Port = CreateFile(
                  "\\\\.\\COM1",
                  GENERIC_READ | GENERIC_WRITE,
                  0,
                  NULL,
                  OPEN_EXISTING,
                  FILE_ATTRIBUTE_NORMAL,
                  NULL);

then check the result.