Ada front-end depends on signed overflow

[Segher Boessenkool]

> Better use a union for the (final) conversion, i.e
>
> int conv(unsigned char *c)
> {
>     unsigned int i;
>     union {
>         unsigned int u;
>         int i;
>     } u;
>
>     u.u = 0;
>     for (i = 0; i < sizeof u; i++)
>       u.u = (u.u << 8) + c[i];
>
>     return u.i;
> }

This is not portable, though; accessing a union member other than
the member last stored into is unspecified behaviour (see J.1 and
6.2.6.1).

This is allowed (and defined behaviour) as a GCC extension, though.


Segher