[Bug preprocessor/35610] New: Pasting "foo" and "(" does not give a valid preprocessing token

[Bug preprocessor/35610] New: Pasting "foo" and "(" does not give a valid preprocessing token

[andry at inbox dot ru]

MSVC++ from 2003 to 2008 and comeau compiler v4.9.3b gives no errors about
that:
//---------------------------------------------
#define CAT(a,b) a ## b

void foo(int a) {}
void foo(int a,int b) {}

int main() {
  CAT(foo,(1));   //error
  CAT(foo,(1,2)); //error
  return 0;
}
//---------------------------------------------


-- 
           Summary: Pasting "foo" and "(" does not give a valid
                    preprocessing token
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: preprocessor
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: andry at inbox dot ru
  GCC host triplet: i686-pc-cygwin


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35610

[Bug preprocessor/35610] Pasting "foo" and "(" does not give a valid preprocessing token

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2008-03-16 22:46 -------
Yes and GCC behavior is correct.  pasting foo and ( don't make a valid
preprocessing token.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID
            Summary|Pasting "foo" and "(" does  |Pasting "foo" and "(" does
                   |not give a valid            |not give a valid
                   |preprocessing token         |preprocessing token


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35610

[Bug preprocessor/35610] Pasting "foo" and "(" does not give a valid preprocessing token

[pinskia at gcc dot gnu dot org]

------- Comment #2 from pinskia at gcc dot gnu dot org  2008-03-16 22:49 -------
## only works to form a valid token, if it does not, then the code is invalid.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35610

[Bug preprocessor/35610] Pasting "foo" and "(" does not give a valid preprocessing token

[andry at inbox dot ru]

------- Comment #3 from andry at inbox dot ru  2008-03-16 22:56 -------
(In reply to comment #2)
> ## only works to form a valid token, if it does not, then the code is invalid.
> 
When i can understand which token is valid then?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35610

[Bug preprocessor/35610] Pasting "foo" and "(" does not give a valid preprocessing token

[pinskia at gcc dot gnu dot org]

------- Comment #4 from pinskia at gcc dot gnu dot org  2008-03-16 23:06 -------
(In reply to comment #3)
> When i can understand which token is valid then?

By reading the C/C++ standards :).  But basically in this case foo and ( are
two different tokens.  Examples of valid tokens: "->", "foo", ".", ",", etc.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35610