Re: C preprocessor failure

[Stephen Olsen <Stephen_Olsen at mentorg dot com>]

Neil,

Thanks for your quick response.  I still think that it is a bug.  Could
you
point me to any specification that says things within #ifdef/#endif's
must
be able to compile even though they are specfically excluded from being
compiled?

I tried cc from sunos, Visual C++ 6.0, 4 cross compilers, and an earlier

version of gcc.  All of them succeeded on this test.  Prior to sending
it
in to you, I handed it over to our compiler guru( we build cross
compilers
here ), and he thought it was a bug.  That is why I submitted it to you.

As I understand it, everything between an #ifdef/#endif, will either be
processed, or ignored.  In GCC's case it is both processed and ignored.
#ifdef's can be used to remove code that is in the process of being
integrated.

One reason that I use #ifdef/#endif's in this manner is to selective add
and
remove code from being processed.  This could be a large block of code
with comments.  It may be code that will not compile for some reason
including
syntax.  That is how I stumbled into this bug.  I was adding some
functions that
would process these strings.  I put them in temporarily so that I can
add the
string processing to produce the same string.

One more thought, I also use the C preprocessor one Assembly files.
This
allows me to have one set of #defines, that select which parts of an
assembly
file actually get processed.  Many assemblers have different ways of
including/
excluding code, so by using the C preprocessor, I have a common way of
including/excluding code from being processed, regardless of the
assembler
syntax.

I appreciate any and all thoughts on this matter.

Sincerely,

Stephen Olsen

Neil Booth wrote:

> Thanks for your bug report.  It is not a GCC bug, but a bug in your
> code; see below.
>
> Stephen Olsen wrote:-
>
> > > #ifdef DO_NOT_PROCESS
> > > <input type=\"text\" name=\"designation\">vendor description
> > >
> > > #endif
>
> You cannot put random text in a source file.  Regardless of the
> setting of DO_NOT_PROCESS, the text in that block must be breakable
> into preprocessing tokens.
>
> The preprocessor does this, as follows:-
>
> <
> input
> type
> =
> \
> "
>
> where the " starts a string but the string never terminates because
> the other quotes are escaped.
>
> Neil.