Re: Macro CHECK_NUMBER?

[Eli Zaretskii]

On Wed, 24 Oct 2001, Pavel =?iso-8859-2?q?Jan=EDk?= wrote:

> in lisp.h we have:
> 
> #define CHECK_NUMBER(x, i) \
>   do { if (!INTEGERP ((x))) x = wrong_type_argument (Qintegerp, (x)); } while 
> (0)
> 
> What is the purpose of having two arguments? What is the meaning of i?

See the block under "#ifdef ENABLE_CHECKING" earlier in lisp.h.  The
second argument is supposed to be a message to print when enhanced
checking of data types is enabled.  I guess this is mostly unused
nowadays, though (since most CHECK_* macros don't have a different
definition under ENABLE_CHECKING), and the second argument is mostly a
NULL pointer.

> Things like this should IMHO: a. be commented or b. not be present in the
> sources (or c. I should buy new glasses).

If we decide to make an effort of documenting this, it should probably
also be in the ELisp manual's internals.texi part, at least some of
the stuff should.