Re: Rethinking octave_idx_type

[John W. Eaton]

On 11/26/2016 11:41 PM, Rik wrote:

> My main idea is that we start to consider performance, [...]
> That's why I would like to know
> whether there is much of a difference in runtimes for the test suite
> between the 32-bit and 64-bit versions of Octave.  Or whether the resident
> set size for the Octave binary is appreciably different between the two.

OK.

> If we change the typedef for octave_idx_type then I think we should make
> several small changes rather than one large destabilizing change.  It would
> be better to move to ssize_t first, where we would only need to modify the
> interaction with the Fortran libraries, rather than size_t, where we would
> also have to find and correct every single instance where negative values
> are used with octave_idx_type.

Yes, this was my plan.

The first step is to use F77_INT instead of octave_idx_type to declare 
integer variables that are passed to Fortran functions.  Currently 
F77_INT is always the same as octave_idx_type, but it shouldn't have to 
be.  Next, allow F77_INT to be whatever is used by the Fortran libraries 
on the system while octave_idx_type can be ssize_t (or ptrdiff_t, or 
whatever signed type it is that has the same number of bits as size_t). 
Then switch octave_idx_type to just be size_t.  Then finally maybe 
replace the octave_idx_type typedef with size_t and just use size_t 
unconditionally for indexing and dimensions as other software typically 
does.

jwe