[Octave-bug-tracker] [bug #60316] New warnings, errors showing up during compilation

[Rik]

Follow-up Comment #8, bug #60316 (project octave):

@Markus: I didn't look too closely at what the gnulib wrapper function does. 
A true replacement for unsigned int would probably be

int
octave_ui_multiply_overflow_wrapper (unsigned int a, unsigned int b,
                                     unsigned int *r)
{
  *r = a * b;
  return 0;
}

This computes the multiplication and always indicates that *no* overflow
occurred.

As far as I can tell, the C standard requires that unsigned integers implement
wraparound semantics.  Therefore, these multiplications are performed the same
everywhere and there are no cross-platform issues.  See, as just one random
reference,
https://www.learncpp.com/cpp-tutorial/unsigned-integers-and-why-to-avoid-them/.

However, the C standard is silent about signed integer multiplications. 
Hence, this becomes compiler and architecture dependendent.  The gnulib
wrappers provide a way of guaranteeing consistency, but that is only necessary
for signed integers.

I will try updating gnulib and see if it helps.  If it doesn't, I suggest we
avoid the macros where they are not required.


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