Re: [libmicrohttpd] How MHD_VERSION works and how to get the "x.y.z-r" string from it?

[FERMIN GALAN MARQUEZ]

Dear Christian, Evgeny,

Thank you very much for the explanations! :)

I'll have a look to MHD_get_version() function. It seems very promising!

Best regards,

------
Fermín

-----Mensaje original-----
De: libmicrohttpd 
<libmicrohttpd-bounces+fermin.galanmarquez=telefonica.com@gnu.org> En nombre de 
Evgeny Grin
Enviado el: miércoles, 28 de octubre de 2020 8:36
Para: libmicrohttpd development and user mailinglist <libmicrohttpd@gnu.org>
Asunto: Re: [libmicrohttpd] How MHD_VERSION works and how to get the "x.y.z-r" 
string from it?

I'd add that current MHD_VERSION is not a mistake. It is widely used special 
notation for versions and it's explicitly mentioned in the header file.
However, the current trend is to use version as real hex numbers (as version 
numbers become higher) so as Christian said it could be changed for MHD as well.

To answer your second question about getting version text string from function. 
We have specialised function named (surprise!) MHD_get_version().
MHD_get_version() returns version's major three numbers (like "0.9.71") as the 
last number in version string is only for developer builds and must be zero for 
any release.

--
Wishes,
Evgeny

Christian Grothoff wrote:
> Hi Fermin,
>
> There isn't a sane way to convert the MHD_VERSION string to the
> x.y.z-string, and it's largely by accident in that we failed to
> properly count in HEX. We are likely to fix that once we go for 1.0.
> OTOH, the idea of the MHD_VERSION string was to do stuff like
>
> #if MHD_VERSION > 0x44
> bug-fixed-or-feature-available
> #else
> workaround-or-warn
> #endif
>
> and not to 'show' the version as a human-readable string. And for
> that, the bug should not matter...
>
> Happy hacking!
>
> Christian
>
> On 10/27/20 7:23 PM, FERMIN GALAN MARQUEZ wrote:
> > Hi,
> >
> >
> >
> > The MHD_VERSION is defined as follows
> >
> >
> >
> > /**
> >
> > * Current version of the library.
> >
> > * 0x01093001 = 1.9.30-1.
> >
> > */
> >
> > #define MHD_VERSION 0x00097000
> >
> >
> >
> > Thus, it seems that by blocks of two digits, each block defines one
> > of the four digits of the usual x.y.z-r version number.
> >
> >
> >
> > Thus, for instance in this case:
> >
> >
> >
> > 00 -> 0. ..
> >
> > 09 -> .. .9. ..
> >
> > 70 -> .. .70
> >
> > 00 -> ..-0
> >
> >
> >
> > resulting in 0.9.70-0. So far so good.
> >
> >
> >
> > However, what has surprised me is that the blocks are interpreted
> > literary instead of hexadecimal (as 0x0 should mean). For instance
> > 70 in hexadecimal is 112 (which would lead to 0.9.112-0 in this case).
> >
> >
> >
> > I have two questions regarding this, please:
> >
> >
> >
> > ·         Why does it work this way? Maybe it’s obvious, but for me is a
> > bit weird J
> >
> > ·         It seems there is no way of getting the “x.y.z-r” text string
> > directly from the libmicrohttpd functions (please, tell me if I’m
> > wrong… I could have missed some function for that provided by the
> > library itself). It would be great if somebody hat has faced before
> > the same problem could share the code snipped to get the “z.y.z-r”
> > text string from the MHD_VERSION hex number :)
> >
> >
> >
> > Thank you very much in advance!
> >
> >
> >
> > Best regards,
> >
> >
> >
> > ------
> >
> > Fermín
> >
> >
> > --------------------------------------------------------------------
> > ----
> >
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