[Mono-dev] System.PlatformID

[Kornél Pál]

Hi,

Try looking at Environment.Version in the prod environment. If you get 
1.1.x rather than 2.0.x you know what your problem is.

Note that only app.config is able to require a specific runtime version, 
and there is no such thing as a 3.5 runtime (it's 2.0 with extra 
assemblies versioned to 3.5.x.x).

Kornél

Nicholas Salerno wrote:
>> It means you're running in the 1.0 profile.  If you were running under
>> the 2.0 profile, you'd get 4 (PlatformID.Unix).
>
> If I write a scratch C# program to show the PlatformID I do get 4.  However, in my production build I am getting 128.  As far as I know the production build should be the 2.0 profile, especially since the build scripts (.proj/.csproj) have some components specifically require 3.5 as the minimum framework version (the whole project is targeted for the 3.5 framework).  If the production assemblies are running as the 1.0 profile I would think something would have not worked properly by now.  I'm a bit puzzled and will look into it.
>
> Thank you for the explanation.
>
> Nicholas
>
> -----Original Message-----
> From: Jonathan Pryor [mailto:jonpryor at vt.edu]
> Sent: Monday, September 20, 2010 10:24 PM
> To: Nicholas Salerno
> Cc: mono-devel-list at lists.ximian.com
> Subject: Re: [Mono-dev] System.PlatformID
>
> On Mon, 2010-09-20 at 18:06 -0400, Nicholas Salerno wrote:
>> When I query System.Environment.OSVersion.Platform on Linux I get a
>> value that will equate to 128.  Yet, this is not in the source code
>> definition for the PlatformID enum.
>
> It means you're running in the 1.0 profile.  If you were running under
> the 2.0 profile, you'd get 4 (PlatformID.Unix).  See:
>
>          http://www.mono-project.com/FAQ:_Technical
>
> Quote:
>
>          The first versions of the framework (1.0 and 1.1) didn't include
>          any PlatformID value for Unix, so Mono used the value 128. The
>          newer framework 2.0 added Unix to the PlatformID enum but,
>          sadly, with a different value: 4 and newer versions of .NET
>          distinguished between Unix and MacOS X, introducing yet another
>          value 6 for MacOS X.
>
>> Question: is 128 supposed to mean Linux?
>
> It means Unix under the 1.x .NET profile; under the .NET 2.0 profile,
> PlatformID.Unix (4) is returned.
>
>> I am wondering if there is a better way or if this is all that can be done.
>
> Targeting .NET 2.0+ will help (no 128 value), but only so much (there's
> still distinct PlatformID.Unix and PlatformID.MacOSX values), so
> preferable (normally) are feature checks, not platform checks.
>
> Feature checks are also more useful anyway, as a feature may be added in
> some version of a platform, and (based on reading years of Dr. GUI
> articles in MSDN) platform version detection and handling is HARD.  You
> would not believe the number of errors applications make doing that...
>
>> Also, what if Microsoft suddenly came out of nowhere and said that 128
>> will map to AIX?
>
> I would laugh.  A lot.  (AIX?!  Seriously?)
>
> The matter still has a theoretical nature, which can be answered thus:
> dontworryaboutit.
>
> More specifically, Mono 2.6 is the last release with 1.x profile
> support, and thus is the last version that will return 128 for
> PlatformID on Unix platforms.  (Plus, most actual apps have been 2.0
> apps for quite some time.).  Mono 2.8 is 2.0+ only, and thus will never
> return 128.
>
> Furthermore, 2.6 is only getting bug fixes (if that), not feature fixes,
> so even if Microsoft added a new enum value, only mono master will
> actually receive the value, not 2.6 (or likely 2.8, at this point).
>
> Thus, in practice, it's not really worth worrying about.
>
>   - Jon
>
>
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