How to register a TLB?

During one conversation, the topic of how to register a TLB in com deployment came up and in the past, I used a less widely publicized program called RegTLIB.exe and from memory, it was installed into my machine as part of Word upgrade or Service Pack or something like that.

Since then, I have lost this program. It is rare to simply distribute the TLB and normally it is better to be embedded into a DLL, a kind of resource only DLL, to leverage the packaged registration script so that user can use the well known system tool Regsvr32.exe to register the TLB.

You can still distribute the TLIB for development but you do not register it unless you use importlib statement in your COM's IDL to import a foreign type library. There is a caveat between importlib and #import statement in developing your COM IDL and it is this:

Note that the imported library, as well as the generated library, must be distributed with the application so that it is available at run time.

The emphasis is on the last four words - available at run time. Failure to do that will cause a run time error. If you are not sure, use OleView to examine your DLL or TLB to see if it uses importlib and how it is used.

Anyway for those that have used importlib to import typelib rather than importlib of a DLL containing the type library, you therefore have to register the type library using a not very commonly available tool. Hence if you are developing COM component, even if you are publishing common interfaces, put the tlb inside the DLL and makes life easy for everyone. While importlib of a DLL does not require you to register the imported type library, you still have to register the imported DLL using RegSvr32. The difference is basically which tool you use to make the type library available at run time - RegTlib or Regsvr32.

In those situations you must register the type library, a lifeline is being offered by .Net framework 2. Go to "%windir%\Microsoft.net\framework\v2.0.50727" and you will find a program called RegTLibv12.exe. Do not expect to find too much information on how to drive this program and MSDN site is devoid of anything even though it has been mentioned several times in Aaron Stebner's blog.

Experimentations with this program tells me this:
* To register MyComStuff.tlb do this:
RegTlibV12 MyComStuff.tlb
* To unregister MyComStuff.tlb do this:
RegTlib -u MyComStuff.tlb
* This program, while distributed with .Net Framework 2, does not use any supporting DLL in the "%windir%\Microsoft.net\framework\v2.0.50727" directory and hence you can safely use it on a machine without .Net 2. Besides, it is a native code program.