Should External Routine Be Declared Always in Fortran?
- by Ngu Soon Hui
In my fortran code I made the following call to dnrm2 routine
d = dnrm2(n, ax, 1)
Just a simple call that would return me a double precision result.
The problem is whether I should declare the function at the start of my script. I found that if I don't declare it, and when I compile the code in 32 bit Windows, then the result is correct.
But if I compile the code in 64 bit Windows, then the result won't be correct.
Why this is so? Is external routine must always be declared?