* Re: Type problem with template functions and inheritance?
@ 2004-09-08 22:41 Wolfgang Bangerth
0 siblings, 0 replies; 3+ messages in thread
From: Wolfgang Bangerth @ 2004-09-08 22:41 UTC (permalink / raw)
To: Simon MARTIN, gcc
> I played a little with templates and template functions, and I encountered a
> problem with GCC while doing so. The code at the end of this message builds
> with Microsoft's Visual C++ Toolkit 2003, but fails with GCC. Since the code
> is quite "weird", I wonder whether there's a problem in GCC or Visual is too
> laxist.
>
> What is strange is:
> - the "<unknown type>" in the error message
> - the fact that if I "help" GCC a little (before the first static_cast),
> then things work fine.
I just opened PR 17359 for this. It seems to me that gcc is wrong indeed.
W.
-------------------------------------------------------------------------
Wolfgang Bangerth email: bangerth@ices.utexas.edu
www: http://www.ices.utexas.edu/~bangerth/
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Type problem with template functions and inheritance ?
2004-09-08 20:10 Type problem with template functions and inheritance ? Simon MARTIN
@ 2004-09-08 21:33 ` Vaclav Haisman
0 siblings, 0 replies; 3+ messages in thread
From: Vaclav Haisman @ 2004-09-08 21:33 UTC (permalink / raw)
To: Simon MARTIN; +Cc: gcc
Because Comeau's test drive compiler accepts I would fill a bug report in
Bugzilla if I were you.
VH
On Wed, 8 Sep 2004, Simon MARTIN wrote:
> Hello.
>
> I played a little with templates and template functions, and I encountered a
> problem with GCC while doing so. The code at the end of this message builds
> with Microsoft's Visual C++ Toolkit 2003, but fails with GCC. Since the code
> is quite "weird", I wonder whether there's a problem in GCC or Visual is too
> laxist.
>
> What is strange is:
> - the "<unknown type>" in the error message
> - the fact that if I "help" GCC a little (before the first static_cast),
> then things work fine.
>
> Thanks in advance for your help / explanation.
>
> Regards,
> Simon
>
> [simon@texel gcc_test]$ g++ -v
> Reading specs from /usr/lib/gcc-lib/i586-mandrake-linux-gnu/3.3.2/specs
> Configured with: ../configure --prefix=/usr --libdir=/usr/lib
> --with-slibdir=/lib --mandir=/usr/share/man --infodir=/usr/share/info
> --enable-shared --enable-threads=posix --disable-checking --enable-long-long
> --enable-__cxa_atexit --enable-clocale=gnu
> --enable-languages=c,c++,ada,f77,objc,java,pascal
> --host=i586-mandrake-linux-gnu --with-system-zlib
> Thread model: posix
> gcc version 3.3.2 (Mandrake Linux 10.0 3.3.2-6mdk)
>
> [simon@texel gcc_test]$ g++ -Wall -o test test.cpp
> test.cpp: In function `int main(int, char**)':
> test.cpp:18: error: invalid static_cast from type `<unknown type>' to type
> `bool (Base::*)(const char*)'
>
> ==== test.cpp
> class Base {};
> struct MyClass : public Base
> {
> template<int key> bool Method(const char *value) { return true; }
> };
>
> int main(int argc, char *argv[])
> {
> typedef bool (Base::*BaseMethodPtr)(const char*);
> typedef bool (MyClass::*MethodPtr)(const char*);
>
> MyClass aClass;
>
> MethodPtr mp = &MyClass::Method<1>;
> BaseMethodPtr p1 = static_cast<BaseMethodPtr>(mp);
> (aClass.*p1)("One");
>
> BaseMethodPtr p2 = static_cast<BaseMethodPtr>(&MyClass::Method<1>);
> (aClass.*p2)("OneAgain");
>
> return 0;
> }
> ==== end of test.cpp
>
> --
> Kile - an Integrated LaTeX Environment for KDE
> http://kile.sourceforge.net
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Type problem with template functions and inheritance ?
@ 2004-09-08 20:10 Simon MARTIN
2004-09-08 21:33 ` Vaclav Haisman
0 siblings, 1 reply; 3+ messages in thread
From: Simon MARTIN @ 2004-09-08 20:10 UTC (permalink / raw)
To: gcc
Hello.
I played a little with templates and template functions, and I encountered a
problem with GCC while doing so. The code at the end of this message builds
with Microsoft's Visual C++ Toolkit 2003, but fails with GCC. Since the code
is quite "weird", I wonder whether there's a problem in GCC or Visual is too
laxist.
What is strange is:
- the "<unknown type>" in the error message
- the fact that if I "help" GCC a little (before the first static_cast),
then things work fine.
Thanks in advance for your help / explanation.
Regards,
Simon
[simon@texel gcc_test]$ g++ -v
Reading specs from /usr/lib/gcc-lib/i586-mandrake-linux-gnu/3.3.2/specs
Configured with: ../configure --prefix=/usr --libdir=/usr/lib
--with-slibdir=/lib --mandir=/usr/share/man --infodir=/usr/share/info
--enable-shared --enable-threads=posix --disable-checking --enable-long-long
--enable-__cxa_atexit --enable-clocale=gnu
--enable-languages=c,c++,ada,f77,objc,java,pascal
--host=i586-mandrake-linux-gnu --with-system-zlib
Thread model: posix
gcc version 3.3.2 (Mandrake Linux 10.0 3.3.2-6mdk)
[simon@texel gcc_test]$ g++ -Wall -o test test.cpp
test.cpp: In function `int main(int, char**)':
test.cpp:18: error: invalid static_cast from type `<unknown type>' to type
`bool (Base::*)(const char*)'
==== test.cpp
class Base {};
struct MyClass : public Base
{
template<int key> bool Method(const char *value) { return true; }
};
int main(int argc, char *argv[])
{
typedef bool (Base::*BaseMethodPtr)(const char*);
typedef bool (MyClass::*MethodPtr)(const char*);
MyClass aClass;
MethodPtr mp = &MyClass::Method<1>;
BaseMethodPtr p1 = static_cast<BaseMethodPtr>(mp);
(aClass.*p1)("One");
BaseMethodPtr p2 = static_cast<BaseMethodPtr>(&MyClass::Method<1>);
(aClass.*p2)("OneAgain");
return 0;
}
==== end of test.cpp
--
Kile - an Integrated LaTeX Environment for KDE
http://kile.sourceforge.net
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2004-09-08 22:41 Type problem with template functions and inheritance? Wolfgang Bangerth
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