Define ei version number in ei.h

[siiky]

Is your feature request related to a problem? Please describe.

Related to this thread. When I learned of ei I tried my hand at implementing a wrapper in my go-to Scheme implementation, and noticed that ei_get_type() returns the ei version number for a full encoded Erlang term. However, because the version is not defined in ei.h, I have to guess that that is the version and not an unknown type.

Describe the solution you'd like

It appears to me that ERL_VERSION_MAGIC could be moved to somewhere around here.

If this is totally intentional and there's a reason for the version not to be publicly defined (maybe I'm holding it wrong?), I would also like to know -- maybe the docs are lacking in some way in that case.

Describe alternatives you've considered

As a temporary workaround, I've defined the version number in the wrapper library. This is not ideal, in case the version changes, although it's also not worrying since the last change was ~15 years ago ^^

[jhogberg]

I suspect that you're using it wrong, the first part of an encoded term is a version that must be decoded with ei_decode_version first.

That ei_get_type returns the first encountered byte is a bit of an accident, I think it should signal failure (-1) instead when encountering a type it does not recognize.

[siiky]

I suspect that you're using it wrong

I wouldn't be surprised, and as long as I learn how to use it correctly, I don't mind. So my thought process previously was to ei_get_type() and then call the corresponding ei_decode_*(). You're saying one should instead call ei_decode_version() before any other ei_get_type()/ei_decode_*(). Is that the intended usage of the library?

[jhogberg]

You're saying one should instead call ei_decode_version() before any other ei_get_type()/ei_decode_*(). Is that the intended usage of the library?

Yes.