Re: #define ExclusiveLock in /usr/include/postgresql/9.1/server/storage/lock.h

Arturas Mazeika <mazeika@gmail.com> writes:
> I would like to express my wonder to see the following line

> #define ExclusiveLock                   7               /* blocks ROW
> SHARE/SELECT...FOR

> (line number 543) in /usr/include/postgresql/9.1/server/storage/lock.h
> file, because ExclusiveLock is a name of a class in libspatialindex library
> (see* *libspatialindex.github.io).

That seems like an awfully strange name for a class ...

> I suppose changing the define to be all capital letters becomes a huge
> problem, doesn't it ?

ExclusiveLock has been defined, with that name, in the Postgres code for
close to 20 years, and there are many references to it both in the core
code and add-ons.  Yes, changing it would be painful.

More generally, we can never promise not to conflict with any identifiers
defined in third-party code.  I don't see any strong reason why we should
do something about this particular case.

I'd suggest arranging your code so that the stuff that deals with
libspatialindex can be in a file separate from code that needs to
know about Postgres internals.  Then you could avoid #include'ing
the conflicting headers in the same source file.
        regards, tom lane