Nesting of a preprocessor directive within a macro defn
Henry Spencer
henry at zoo.toronto.edu
Sun Sep 2 12:20:39 AEST 1990
In article <849 at gtenmc.UUCP> ravim at gtenmc.UUCP (Ravi Kumar Mandava) writes:
>Is nesting of a preprocessor directive within a macro definition (RHS) not
>allowed?
It is not possible. The very first thing that happens to ANSI C source
during compilation is that backslashed newlines are stripped out, so any
"#" within the RHS is no longer at the start of a line and hence does
not begin a preprocessor directive.
(And incidentally, the result of macro expansion "is not processed as a
preprocessing directive even if it resembles one", section 3.8.3.4.)
Some old C compilers may have permitted such things, due to the vagueness
of the old definition of how the preprocessor features interacted.
--
TCP/IP: handling tomorrow's loads today| Henry Spencer at U of Toronto Zoology
OSI: handling yesterday's loads someday| henry at zoo.toronto.edu utzoo!henry
More information about the Comp.lang.c
mailing list