RE: [Dev-C++] #DEFINE versus cont variables in array inicializations

> -----Original Message-----
> From: dev...@li... 
> [mailto:dev...@li...] On Behalf 
> Of Ioannis Vranos
> Sent: Saturday, May 31, 2003 3:22 AM
> To: Dev-C++ Mailing List
> Subject: RE: [Dev-C++] #DEFINE versus cont variables in array 
> inicializations
> 
> 
> I just checked it and it seems you are right. Don't know why yet.
> 
> 
> However does the above style make the compiler to give it an 
> address? That
> would be very strange. I shall check the standard now.


TC++PL on pages 199,200 says that const has by default internal linkage. So
the definition must be accomanied by the keyword extern too.


So my code becomes:


temp2.cpp:

extern const int x=17;


temp.cpp:

#include <iostream>


extern const int x;


int main()
{
 const unsigned char *p=reinterpret_cast<const unsigned char *>(&x);
 
 
 // Shows x representation in memory in byte values
 // including padding bits
 for(unsigned long i=0; i<sizeof(x); ++i)
   std::cout<<static_cast<short>(p[i])<<" ";


}


C:\c>g++ temp.cpp temp2.cpp -o temp

C:\c>temp
17 0 0 0
C:\c>


So in this case the compiler can know if the const object or *reference* is
accessed in another translation unit.



However why a compiler would "inline" const int x=7; and  would not be able
to "inline" const int &x=7; isn't clear and would be nice if you explained
it to us. And please do not involve L1/L2 caches, we are talking about
inline substitution here. And my CPU may have no cache.




Ioannis Vranos
 
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