• Scott Michel <scottm cs.ucla.edu> Jan 27 2004
• Scott Michel <scottm cs.ucla.edu> Feb 02 2004
• Scott Michel <scottm cs.ucla.edu> Feb 02 2004
• "Walter" <walter digitalmars.com> Feb 06 2004

Scott Michel <scottm cs.ucla.edu> writes:

Here's the simplified code example that demonstrates that static template
objects do not get constructed when its DLL get's loaded. Unfortunately, I
have a lot of these in my code and the problem affects me critically.

---------------------------------------------------------------------
#include <iostream>

template<typename T> struct dllmain_foo
{
        dllmain_foo();
};

template<typename T>
dllmain_foo::dllmain_foo()
{
        std::cout << "dllmain_foo constructed" << std::endl;
}

typedef dllmain_foo<int> dllmain_foo_int;

static dllmain_foo_int dllmain_foo_int_wombat;
----------------------------------------------------------------------

I'd expect "dllmain_foo constructed" to show up when tested in a
console-mode app, but it doesn't. If I make dllmain_foo just a regular
structure (non-template), the expected output shows up.


-scooter

Scott Michel <scottm cs.ucla.edu> writes:

Slightly better console mode program that demonstrates that the static 
template object's ctor doesn't get invoked. Oddly enough, I could work 
around this problem with an anonymous namespace:

#include <iostream>

//---------------------------------------------------------------------------

template<typename T>
struct problem_1
{
     problem_1();
    ~problem_1();
};

template<typename T>
problem_1<T>::problem_1()
{
     std::cout << "problem_1 ctor invoked." << std::endl;
}

template<typename T>
problem_1<T>::~problem_1()
{
     std::cout << "problem_1 dtor invoked." << std::endl;
}

// Should be initialized but isnt (no output from ctor):
static problem_1<int> static_problem_1;

//---------------------------------------------------------------------------

namespace {
         template<typename T>
         struct problem_2
         {
             problem_2();
            ~problem_2();
         };

         template<typename T>
         problem_2<T>::problem_2()
         {
             std::cout << "problem_2 ctor invoked." << std::endl;
         }

         template<typename T>
         problem_2<T>::~problem_2()
         {
             std::cout << "problem_2 dtor invoked." << std::endl;
         }
};

// But the anonymous namespace DTRT:
problem_2<int>  anon_problem_2;

//---------------------------------------------------------------------------

int main(void)
{
     std::cout << "hello from main." << std::endl;
}

Scott Michel <scottm cs.ucla.edu> writes:

Scott Michel wrote:

 Slightly better console mode program that demonstrates that the static
 template object's ctor doesn't get invoked. Oddly enough, I could work
 around this problem with an anonymous namespace:


Let me clarify: I can work around the problem in the example's code with an
anonymous namespace. I can't necessarily be so cavalier with my research
code.


-scooter

"Walter" <walter digitalmars.com> writes:

"Scott Michel" <scottm cs.ucla.edu> wrote in message
news:bvmqak$2tvn$1 digitaldaemon.com...
 Scott Michel wrote:

 Slightly better console mode program that demonstrates that the static
 template object's ctor doesn't get invoked. Oddly enough, I could work
 around this problem with an anonymous namespace:


 Let me clarify: I can work around the problem in the example's code with


 anonymous namespace. I can't necessarily be so cavalier with my research
 code.


I understand, and I can reproduce the problem. I'll try and fix it.