prob in compilation with gcc3.4

prob in compilation with gcc3.4

[Deepak Soi]

Hi,
       I am getting a compilation error with gcc3.4. Is there some 
special handling of macros in gcc3.4 as all these lines are calling 
macros . It will be really nice if somebody helps out, I am struck.
==============================================================
  find.cxx:723:1: pasting "DbNet" and "*" does not give a valid 
preprocessing token.
  find.cxx:723:1: pasting "Net" and "*" does not give a valid 
preprocessing token.
  find.cxx:723:1: pasting "FindFromDbNet" and "(" does not give a valid 
preprocessing token.
==================================================================

regards
Deepak

Re: prob in compilation with gcc3.4

[Ian Lance Taylor]

Deepak Soi <sdeepak@cadence.com> writes:

>        I am getting a compilation error with gcc3.4. Is there some
> special handling of macros in gcc3.4 as all these lines are calling
> macros . It will be really nice if somebody helps out, I am struck.
> ==============================================================
>   find.cxx:723:1: pasting "DbNet" and "*" does not give a valid
> preprocessing token.
>   find.cxx:723:1: pasting "Net" and "*" does not give a valid
> preprocessing token.
>   find.cxx:723:1: pasting "FindFromDbNet" and "(" does not give a
> valid preprocessing token.
> ==================================================================

Sounds like invalid use of ##, which is used to paste two tokens
together into a single token.  The problem is going to be somewhere
inside your macro definitions.  Perhaps you are simply using an
inappropriate argument to your macro.  It's impossible to say much
more without an example.

Ian

problem with pasting two tokens together in gcc 3.4

[Deepak Soi]

Hi,       
       Yes, you are right problem we are facing is with pasting two 
tokens together, but what I am unable to understand is why its compiling 
properly with older gcc versions. Is there any change in gcc3.4 handling 
of macros.I will be thankful for your help on this.

======================================================================
Error

 find.cxx:723:1: pasting "DbNet" and "*" does not give a valid 
preprocessing token.

  find.cxx:723:1: pasting "Net" and "*" does not give a valid
preprocessing token.
  find.cxx:723:1: pasting "FindFromDbNet" and "(" does not give a
valid preprocessing token.

=====================================================================

regards
Deepak Soi




Ian Lance Taylor wrote:

>Deepak Soi <sdeepak@cadence.com> writes:
>
>  
>
>>       I am getting a compilation error with gcc3.4. Is there some
>>special handling of macros in gcc3.4 as all these lines are calling
>>macros . It will be really nice if somebody helps out, I am struck.
>>==============================================================
>>  find.cxx:723:1: pasting "DbNet" and "*" does not give a valid
>>preprocessing token.
>>  find.cxx:723:1: pasting "Net" and "*" does not give a valid
>>preprocessing token.
>>  find.cxx:723:1: pasting "FindFromDbNet" and "(" does not give a
>>valid preprocessing token.
>>==================================================================
>>    
>>
>
>Sounds like invalid use of ##, which is used to paste two tokens
>together into a single token.  The problem is going to be somewhere
>inside your macro definitions.  Perhaps you are simply using an
>inappropriate argument to your macro.  It's impossible to say much
>more without an example.
>
>Ian
>  
>

Re: problem with pasting two tokens together in gcc 3.4

[Arturas Moskvinas]

>        Yes, you are right problem we are facing is with pasting two
> tokens together, but what I am unable to understand is why its compiling
> properly with older gcc versions. Is there any change in gcc3.4 handling
> of macros.I will be thankful for your help on this.

You could write the version where this "kind" of thing worked, then it
would be easier to answer to your question.

Arturas Moskvinas

Re: problem with pasting two tokens together in gcc 3.4

[Nix]

On 18 May 2005, Deepak Soi moaned:
> Hi, Yes, you are right problem we are facing is with pasting two
> tokens together,

You shouldn't use ## to paste two tokens together if there result would
be parsed as two tokens (as is the case below). Its purpose is to paste
two tokens together to yield *one* token. That is,

#define IdentifierComposition (x, y) x##y
IdentifierComposition(Some,Function)

would yield the *single token* `SomeFunction'.

>                  but what I am unable to understand is why its
> compiling properly with older gcc versions. Is there any change in
> gcc3.4 handling of macros.

The preprocessor was rewritten completely before GCC 3.0, and has got
progressively stricter (i.e. more standards-compliant) since then.
I believe even GCC-3.0 complained about this (erroneous) construct,
but I'm not certain.

>  find.cxx:723:1: pasting "DbNet" and "*" does not give a valid preprocessing token.
>   find.cxx:723:1: pasting "Net" and "*" does not give a valid
> preprocessing token.
>   find.cxx:723:1: pasting "FindFromDbNet" and "(" does not give a
> valid preprocessing token.

You shouldn't be using ## in any of those cases. Exactly how your macros
should be restructured depends on what the macros are doing, but probably
you can replace a##b with a simple `a b'.

-- 
`End users are just test loads for verifying that the system works, kind of
 like resistors in an electrical circuit.' - Kaz Kylheku in c.o.l.d.s