Re: [PATCH] lib/xstrtol.c: Fix xstrtol() on EINVAL (invalid base)

[Paul Eggert]

On 2024-07-24 12:27, Alejandro Colomar wrote:
> POSIX leaves the value of *endptr unspecified if the base is invalid;
> it is not unmodified.

Fine, we can let xstrtol do the same.


> That, combined with the fact that POSIX allows implementations of
> strtol(3) to set EINVAL when no digits are found, makes it impossible to
> portably check if the base was valid after the call.

I don't see why not. Current gnulib xstrtol.c does something reasonable 
if the base is invalid. Why isn't that good enough?


> -  char *t_ptr = nullptr;
> +  char *t_ptr;
>     char **p = endptr ? endptr : &t_ptr;
>   
> +  *p = (char *) nptr;
> +
> +  if (base < 0 || base == 1 || 36 < base)
> +    return LONGINT_INVALID;
> +

This would cause xstrtol to fail even if the underlying strtol supports 
base 1, base 64, etc. Why would we want to do that?


> I'm tired of strtol(3).  :)

Likewise. This issue about an invalid base is unimportant in practice, 
as the base is almost invariably a valid constant.