Paul Kranenburg <pk@cs.few.eur.nl> writes:

> >#define SHMLBA sysconf(_SC_PAGESIZE)

> Is there any standards document saying that SHMLBA cannot be a
> non-compile-time constant like this?

An implementation may choose to do that.

However, this brings up a new problem - including <unistd.h> will pull
in far too much clutter, and requiring the application to do so itself
isn't acceptable.  For the time being I think we could live with a
additional sysconf() declaration in that place, but ideally we should
replace it with a private name (i.e. __sysconf()).