Re: enum vs int and API/ABI compatibility

[Simon Josefsson]

Paul Eggert <address@hidden> writes:

> On 10/19/11 04:06, Simon Josefsson wrote:
>> 1) Is there any platform where this has any implications for the ABI?
>
> OS/400.  libcurl ran into this problem; see
> <http://multitheftauto.googlecode.com/svn/trunk/vendor/curl/packages/OS400/README.OS400>.
>
> Android users are constantly worrying about whether to compile
> with -fno-short-enums, citing ABI incompatibilities.  E.g., see
> <http://osdir.com/ml/android-ndk/2010-10/msg00559.html>.
>
> I expect you'll probably run into an ABI problem somewhere,
> though I couldn't find anything specifically on point to your
> coding example.

Ouch. :-(

Thanks for this information.  I feared that the old assumption "enum =
int" that I have relied on wasn't really true.

It's still not clear to me that my proposed change would break on even
OS/400 though, it seems the curl problem was only about varargs?  They
used a pragma to turn enum into int's, but it wasn't clear that the
compiler would pick something else if the pragma wasn't there.

/Simon