Preprocessor macro to quote its argument

[Henry Spencer]

In article <11517 at ogicse.ogi.edu> schaefer at ogicse.ogi.edu (Barton E. Schaefer) writes:
>Now wait a minute here -- is it really true that the "right hand side"
>of a #define constant must be a valid token sequence?  I was under the
>impression that only the result after expansion had to be a valid sequence.

Your impression is wrong; the RHS of a #define constant must be a sequence
of valid preprocessor tokens (which are somewhat less restrictive than
"real" tokens).  In particular, mismatched quotes have undefined effects.

The right way to fix the notorious `CTRL(D)' problem is to quote the D.
There is no portable way for the macro to supply the (single) quotes.
This has been true for a long time; tokenizing preprocessors existed
well before the ANSI C effort started.
-- 
Committees do harm merely by existing. | Henry Spencer at U of Toronto Zoology
                       -Freeman Dyson  |  henry at zoo.toronto.edu   utzoo!henry