Re: [PATCH v1] xstrtol: Remove dead code

[Bruno Haible <bruno@clisp.org>]

Hi Alejandro,

> strtol(3) has a limited set of possible states:
> ...
> The condition '*endp != s && errno != 0 && errno != ERANGE' is
> unreachable.  The only errno possible if '*endp != s' is ERANGE.

Such a statement can be true if you look at the standards (ISO C, POSIX).

However, there's a difference between what the standards say and what the
systems actually do. The Gnulib documentation contains thousands of examples
of such differences.

Gnulib therefore (almost) never assumes that there are no possible errno
values besides the ones listed in the standards.
  - Some systems return "wrong" errno values. Example: [1]
  - Some systems fail with ENOMEM when memory is tight. Who says that
    an implementation of strtol() cannot use malloc() ? Some implementations
    of strtod() do use malloc().

So, what you call "dead code", I call "defensive programming". I would not
like to apply this patch.

Bruno

[1] https://www.gnu.org/software/gnulib/manual/html_node/getlogin_005fr.html