Mailinglist Archive: opensuse-programming (84 mails)

[John Lamb <J.D.Lamb@xxxxxxxxxxxxxx>]

Colin Carter wrote:
> Does anybody know if SuSE 64 bit system is really 64 bit code?
> I can't seem to get any response from SuSE staff regarding 
> the questions:
> 1: If I define   int i;  and real x;
>    do I get 64 bit integer and float if compiled under 64?

Try it and see:

#include<stdio.h>
int main() {
  printf( "short has size %d\n", sizeof( short ) );
  printf( "int has size %d\n", sizeof( int ) );
  printf( "long has size %d\n", sizeof( long ) );
  printf( "long long long has size %d\n", sizeof( long long ) );
  printf( "float has size %d\n", sizeof( float ) );
  printf( "double has size %d\n", sizeof( double ) );
}

A 32-bit system will give 2 for short, 4 for int, long and float and and 
8 for long long and  double. A 64-bit system ought to give different 
values. Remember that C also specifies bounds for some of these values; 
so short isn't going to have size 8 just because you've got 64-bit code.

> 2: Where does one find the definitions in the SuSE system?
>    For example, where is the definition for the structure of
>    XSizeHints ?
>    Where is the definition of the function prototypes for the
>    64 bit functions?

Typically somewhere in the /usr/include hierarchy.

> Maybe the 'average' programmer can ignore such issues, but I
> want to use FORTRAN to do the number crunching and I need to
> know if I should pass an integer(KIND=4) or integer(KIND=8)

I don't suppose there's any way I could persuade you to try using C++ or 
C instead of FORTRAN (I gave up FORTRAN in 1988 and haven't looked 
back). If you're calling C functions, then I guess you just look for the 
declarations in an include directory and use the program above (compile 
it gcc name.c and run it ./a.out) to identify the actual sizes.

--
JDL