Re: [bug-gnulib] [bug-gnulib] New getlogin_r module

[Bruno Haible]

Derek Price wrote:
> +int
> +getlogin_r (char *name, size_t size)
> +{
> +  char *n = getlogin ();
> +  if (n)
> +    {
> +      size_t nlen = strlen (n);
> +      if (nlen < size)
> +        {
> +          memcpy (name, n, nlen + 1);
> +          return 0;
> +        }
> +      errno = ERANGE;
> +    }
> +  return -1;
> +}

The return value is incorrect, and the getlogin () return conventions are
ignored.

http://www.opengroup.org/onlinepubs/009695399/functions/getlogin.html
says:

  "Upon successful completion, getlogin() shall return a pointer to the login
   name or a null pointer if the user's login name cannot be found.
   Otherwise, it shall return a null pointer and set errno to indicate the
   error."

Which means, you need to set errno = 0 before calling getlogin(), to
distinguish two of the three cases.

And

  "If successful, the getlogin_r() function shall return zero; otherwise,
   an error number shall be returned to indicate the error."

So, instead of "errno = ERANGE; return -1; " you need to do "return ERANGE;".

Bruno