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very complicated error. Maybe someone here has enough C++ knowledge :)

problem.cpp

Code:

namespace util { 

        class CSys 

        { 

        public: 

        CSys(void); 

        ~CSys(void); 

        int operator() () {return 8;} 

        }; 



        CSys sys1; 

        CSys &sys=sys1;

} 



util::CSys::CSys()

{

}



util::CSys::~CSys()

{

}



void this_cause_error()

{

        util::sys(); // error in gcc : "error, cannot be used as a fuction" 

}



using namespace util; 



int main(int /* argc */, char* /* argv[] */) 

{ 

        // these 5 lines will call same operator

        util::sys.operator() (); // OK 

        sys.operator() (); // OK 

        sys(); // OK 



        this_cause_error();

        util::sys(); // error in gcc : "error, cannot be used as a fuction" 

}

in Visual C++ .NET, everything is fine, but gcc won't even compile, because of util::sys();

Seems like specifying namespace is causing him trouble, because other 2 lines compile without error

I'm using gcc 3.3.4.
Am I doing something wrong or gcc has a bug ?

EDIT : Well newest gcc is 3.4.1, so maybe I should upgrade, but I just want to know if problem is in gcc or in my code

my gcc 3.2 (mingw) compiles this code without problem
I'll start GNU/Linux and try with gcc 2.95 and 3.4.3 now...

Edit in GNU/Linux: Yes you can just update to gcc 3.4.1 and the program will be solved...
gcc 2.95 also has this bug. Also the "3.4.3" is a typo

here is report from gcc :

gcc -v -save-temps problem.cpp

Reading specs from /usr/lib/gcc-lib/i486-slackware-linux/3.3.4/specs
Configured with: ../gcc-3.3.4/configure --prefix=/usr --enable-shared --enable-t
hreads=posix --enable-__cxa_atexit --disable-checking --with-gnu-ld --verbose --
target=i486-slackware-linux --host=i486-slackware-linux
Thread model: posix
gcc version 3.3.4
/usr/lib/gcc-lib/i486-slackware-linux/3.3.4/cc1plus -E -D__GNUG__=3 -quiet -v -
D__GNUC__=3 -D__GNUC_MINOR__=3 -D__GNUC_PATCHLEVEL__=4 -D_GNU_SOURCE problem.cpp
problem.ii
ignoring nonexistent directory "/usr/i486-slackware-linux/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/include/c++/3.3.4
/usr/include/c++/3.3.4/i486-slackware-linux
/usr/include/c++/3.3.4/backward
/usr/local/include
/usr/lib/gcc-lib/i486-slackware-linux/3.3.4/include
/usr/include
End of search list.
/usr/lib/gcc-lib/i486-slackware-linux/3.3.4/cc1plus -fpreprocessed problem.ii -
quiet -dumpbase problem.cpp -auxbase problem -version -o problem.s
GNU C++ version 3.3.4 (i486-slackware-linux)
compiled by GNU C version 3.3.4.
GGC heuristics: --param ggc-min-expand=98 --param ggc-min-heapsize=128570
problem.cpp: In function `void this_cause_error()':
problem.cpp:25: error: `util::sys' cannot be used as a function
problem.cpp: In function `int main(int, char*)':
problem.cpp:38: error: `util::sys' cannot be used as a function

By using util::sys() the compiler thinks you're trying to call a function [sys] in namespace util. The only thing it can match it against is a variable - hence the compiler output. If some variations of the compiler pick it up as a variable first, then it will still compile - the but the code is ambiguous in this respect and so should be changed anyway.

Also unless you mean to use things like operator overloading (+, -, *, /, etc) with a class, you should probably try and avoid the name "operator" for a function, as it may also cause a few complications.

Quote:

Originally Posted by mirv

Also unless you mean to use things like operator overloading (+, -, *, /, etc) with a class, you should probably try and avoid the name "operator" for a function, as it may also cause a few complications.

Well my problem was whole about operator overloading.

Code:

int operator() () {return 8;}

operator() is operator. It is very nice operator, you can work with class as if it was function. Another cool operator is opeartor bool(), which allows you to include your class in if statements...