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G++ refuses to template class code, ms compiler is happy

0 votes
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I'm not a c++/template guru and i can't decide if this is really a valid code or i have encountered a gcc bug:

template  struct A {
 void *p;
};
template  struct B : A {
 void *foo() { return p; }
};

g++ says "error: 'p' was not declared in this scope". microsoft's compiler is happy with the same code.

Can anyone help?

posted Jun 14, 2013 by anonymous

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1 Answer

+1 vote

Current MSVC in standard C++ mode? That's odd.

The compiler doesn't now the members of A when the B template is compiled. (There might be a partial specialization later in the file.) Therefore, you must explicitly request dependent name lookup by
dereferencing the this pointer:

template  struct B : A {
 void *foo() { return this->p; }
};
answer Jun 14, 2013 by anonymous
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0 votes

This code compiles on MSVC but not on G++ :

template
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{
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class A
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void test()
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The error with g++ is :

test.cpp: In static member function "static void B::SomeMethod()":
test.cpp:7:3: error: "A" has not been declared

Is there is a option to indicate to g++ to evaluate the template functions only when a specialization is called, and not before ?

–1 vote

I have a c++ shared object that I am compiling using the following command.
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And I am creating the shared object using the following command.
g++ -shared -o libcpplib.so cpplib.o

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My host runs a RedHat 6.x x86_64 OS.

The compilation fails with the following error.

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/usr/lib/gcc/x86_64-redhat-linux/4.4.7/libstdc++.a: could not read symbols: Bad value
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0 votes

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float sum (int M, float x[M]) {
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}

int main (void) {
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 return 0;
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But it is rejected by g++ --std=gnu++11. Is this possible at all with g++?

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I am new to C+ and I wonder why this code compiles fine with g+ and MSVC:

 namespace t {

 class A {
 public:
 int i;
 };

 int b(int k, A a) {
 return k;
 }

 }

 int main()
 {
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 return b(5, cl);
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I thought that b should not be visible from the main function.

0 votes

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Is this expected behavior for functions marked as constructors (compiled with -O0)?

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