EnumSerialPorts v1.17 A set of functions to enumerate serial ports

One of the posts that keeps reappearing in the programming newsgroups is how to enumerate all the serial ports installed. The code uses a number of different methods to enumerate the ports.

Features

• Simple C++ class interface.
• The code works on both Windows 95/98, NT, Windows 2000, XP, 2003 and Vista.
• The code is fully Unicode compliant and include Unicode built options in the workspace file.
• Internally the code provides 7 different ways (yes you read that right: Seven) of enumerating serial ports: Using CreateFile, QueryDosDevice, GetDefaultCommConfig, two ways using the Setup API, EnumPorts and finally WMI.

The enclosed zip file contains the EnumSerialPorts source code and a simple console based application which exercises the functions.

Copyright

• You are allowed to include the source code in any product (commercial, shareware, freeware or otherwise) when your product is released in binary form.
• You are allowed to modify the source code in any way you want except you cannot modify the copyright details at the top of each module.
• If you want to distribute source code with your application, then you are only allowed to distribute versions released by the author. This is to maintain a single distribution point for the source code.

Updates

v1.0 (3 November 1998)

• Initial Public release.

v1.01 (23 February 1999)

• Code now uses QueryDosDevice if running on NT to determine which serial ports are available. This avoids having to open the ports at all. It should operate a lot faster in addition

v1.02 (12 December 1999)

• Fixed a problem in the Win9x code path when trying to detect deactivated IRDA-ports. When trying to open those, you will get the error-code ERROR_GEN_FAILURE. 

v1.03 (17 May 2000)

• Code now uses GetDefaultCommConfig in all cases to detect the ports.

v1.04 (29 March 2001)

• Reverted code to use CreateFile or QueryDosDevice as it is much faster than using the GetDefaultCommConfig method.
• Updated copyright message.

v1.05 (25 June 2001)

• Guess what, You now have the choice of using the GetDefaultCommConfig thro the use of three versions of the function. You take your pick.

• Fixed problem where port fails to be reported thro the CreateFile mechanism when the error code is ERROR_SHARING_VIOLATION i.e. someone has the port already open.

v1.06 (11 August 2001)

• Made code path which uses QueryDosDevice more robust by checking to make sure the device name is of the form "COMxyz.." where xyz are numeric.

v1.07 (13 August 2001)

• Made the code in IsNumeric more robust when sent an empty string

• Optimized the code in EnumerateSerialPorts2 somewhat. Thanks to Dennis Lim for these suggestions.

v1.08 (22 May 2003)

• Updated copyright details.

• Addition of a EnumerateSerialPorts4 which uses Device Manager API

v1.09 (20 September 2003)

• Addition of a "EnumerateSerialPorts5" method. This method (hopefully the last method!) uses EnumPorts and was provided by Andi Martin.

v1.10 (12 December 2003)

• Updated the sample app to VC 6.
• Addition of a "EnumerateSerialPorts6" (See Note 4 below) which uses WMI.
• You can now optionally exclude each function using preprocessor defines of the form "NO_ENUMSERIAL_USING_XYX".
• Made the functions members of a C++ class and renamed them to using more meaningful names

v1.11 (13 May 2004)

• Extended CEnumerateSerial::UsingSetupAPI to now also return the friendly name of the port. Thanks to Jay C. Howard for prompting this update.

v1.12 (9 July 2006)

• Updated copyright details.
• Addition of a CENUMERATESERIAL_EXT_CLASS macro to allow the code to be easily added to an extension dll.
• Code now uses newer C++ style casts instead of C style casts.
• Updated the code to clean compile on VC 2005.
• Updated the documentation to use the same style as the web site.

v1.13 (8 November 2006)

• Extended CEnumerateSerial::UsingWMI to now also return the friendly name of the port. Thanks to Giovanni Bajo for providing this update.
• Fixed a bug where CEnumerateSerial::UsingSetupAPI forget to empty out the Friendly name array on start.
• VariantInit is now called for the 2 VARIANT structs used in the UsingWMI method code.

v1.14 (29 January 2007)

• Updated copyright details.
• UsingSetupAPI code now uses the GUID_DEVINTERFACE_COMPORT guid to enumerate COM ports. Thanks to David McMinn for reporting this nice addition.
• Detection code which uses CreateFile call, now treats the error code of ERROR_SEM_TIMEOUT as indication that a port is present.

v1.15 (9 June 2007)

• Following feedback from John Miles, it looks like my previous change of the 29 January 2007 to use GUID_DEVINTERFACE_COMPORT in the UsingSetupAPI method had the unintended consequence of causing this method not to work on any versions of Windows prior to Windows 2000. What I have now done is reinstate the old mechanism using the name UsingSetupAPI2 so that you can continue to use this approach if you need to support NT 4 and Windows 9x. The new approach of using GUID_DEVINTERFACE_COMPORT has been renamed to UsingSetupAPI1.

v1.16 (5 July 2007)

• Updated the code to work if the code does not include MFC. In this case, CUIntArray parameters becomes the ATL class CSimpleArray<UINT> and CStringArray parameters become the ATL class CSimpleArray<CString>. Please note that this support requires a recentish copy of Visual Studio and will not support Visual C++ 6.0 as the code makes use of the ATL CString class. Thanks to Michael Venus for prompting this update.
• CEnumerateSerial::UsingWMI method now uses ATL smart pointers to improve robustness of the code.

v1.17 (20 March 2008)

• Updated copyright details
• Updates to preprocessor logic to correctly include UsingSetupAPI1 and UsingSetupAPI2 functionality
• Updated sample app to clean compile on VC 2008