perlapi: Combine Strtod, my_strtod

[khwilliamson]

And clarify the pod

[jkeenan]

When calling perldoc pod/perlapi.pod in the file generated from building your branch, I read:

    "my_strtod"
    "Strtod"
        These are identical.

... and then later I see the signatures:

            NV  my_strtod(const char * const s, char **e)
            NV  Strtod   (const char * const s, char ** e)

... which, on the face of it, are not identical. Is the wordspace before the final e material? If not, can we make the signature end in char**e in both instances?

[mauke]

The space is immaterial. As far as C is concerned, char**e and char * * e are the same token sequence and are parsed the same way.¹

I think this line in perl.h is responsible for giving Strtod the extra space:

=for apidoc AmTR|NV|Strtod|NN const char * const s|NULLOK char ** e

---

¹ I'd never write char**e (without any spaces) though, because the * is syntactically a unary prefix operator. Fully parenthesized, the declaration would be char (*(*(e))), i.e. it's all grouping to the right.

[tonycoz]

NV isn't the largest precision enabled, otherwise it would always be __float128 on gcc.

It's just the floating point type perl is configured to use.