What is VERSIONINFO.InternalName of a dll?

Question

The VERSIONINFO resource has an InternalName property. Why is this needed and what is its meaning? Is it a required property for every dll? How is this property used?

Answer 1

Fairly subjective, but VERSIONINFO certainly looks like it was designed by a committee instead of a programmer. They didn't know when to stop adding features and everybody got something in that they thought was important. The exact reasoning is lost in the fog of time and MSDN isn't specific enough to guess at the intention.

At least part of the schizophrenia is that the resource is intended both to be read by a human, it fills the Details property sheet that you see in Explorer, as well as machine readable through GetFileVersionInfo() and friends. A particularly painful winapi to use. This does for example somewhat explain the oddity of having two ways to specify the file and product version numbers. Both as a binary number and as a string. With the intention that the string can be localized, perhaps.

InternalName fits the machine-readable usage, note how it does not show up in the Details property sheet. Which makes it "internal", perhaps. And note that the OriginalFilename property does show up, thus intended for a human.

There is very little guidance on why it matters since there is no fixed usage of the property. It doesn't show up on the property sheet and afaik it doesn't get used by Windows itself at all. It is therefore completely up to you want you enter here, do note that it is required property. Maybe you'll have a use for it some day, I personally never found one. Just enter the name of the module as you originally specified it in your spec, simply set OriginalFilename to the same string with, say, .dll appended.