initialization of static reference.

[John Smith]

Hello group.

In the following snipet of code is it guaranteed that foo::coords_
will be initialized before foo::active_coord_ ?

I mean is it guaranteed that the reference &active_coord_ will be
valid ?

Thanks a lot for your response.

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

#include <vector>
#include <iostream>

class foo {
public:
static std::vector<size_t> coords_;
static size_t &active_coord_;
};

std::vector<size_t> foo::coords_( 1 );

size_t &foo::active_coord_ = coords_[ 0 ]; // Is it safe ?

int main() {
foo ob;

foo::coords_[ 0 ] = 10;
std::cout<<" active coord is "<<ob.active_coord_<<"\n";

return 0;
}

 

[Zeppe]

Yes, until 'coords_' vector chooses to reallocate its memory.

Unfortunately this leads to very nasty bugs that are not easy to
discover. Of course, if the maximum solution is known, it's always
possible to preallocate with reserve().

Best wishes,

Zeppe