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Re: c++/2288: Variable declared in for-loop-header is in wrong scope
- From: Wolfgang Bangerth <bangerth at ticam dot utexas dot edu>
- To: gcc-gnats at gcc dot gnu dot org, <gcc-bugs at gcc dot gnu dot org>
- Date: Thu, 14 Nov 2002 18:13:47 -0600 (CST)
- Subject: Re: c++/2288: Variable declared in for-loop-header is in wrong scope
Still happens with recent CVS. A smaller, self-contained testcase is this:
------------------------
void f(int);
int main() {
for (int i=0;;++i) {
int i=5;
f(i);
}
return 0;
}
-----------------------
I don't get an error upon the second declaration of "i", although it
should be in the same scope as that declared in the loop-header. If I use
-Wshadow, it says
x.cc: In function `int main()':
x.cc:4: warning: declaration of `i' shadows a previous local
x.cc:3: warning: shadowed declaration is here
So one can assume that gcc generates two nested scopes for this construct,
in the outer one those variables are placed which are declared in the loop
header, in the inner one those go that are declared in the loop body. I
think this is not the intent of the standard...
The C frontend in gnu99 mode suffers from the same problem, by the way.
Regards
Wolfgang
-------------------------------------------------------------------------
Wolfgang Bangerth email: bangerth@ticam.utexas.edu
www: http://www.ticam.utexas.edu/~bangerth