Re: [Mesa3d-dev] Re: mesa assuming glibc 2.2? (Cannot compile4.1 on RedHat 6.2)

[Mike A. H. <mh...@re...>]

On Tue, 5 Jun 2001, Brian Paul wrote:

>> Then in order to use SSE on a machine at runtime, one must have
>> an SSE capable machine to build on?  I don't like the sound of
>> that, even if my box has SSE.  IMHO, the build host should be
>> independant of the runtime host.
>>
>> Perhaps I am misunderstanding the above comments?
>
>Perhaps so.  At runtime, the Mesa code tries to execute some SSE
>instructions and checks if it works or not.  It might fail because
>there's no kernel support or you're using a CPU without SSE
>instructions.  This is done with an exception handler.
>
>Now at compile time we need at least a certain version of the system
>headers in order to compile the exception handler code.
>If we don't have the right headers, we can't compile the code.  I'm
>just saying that I'd rather the compilation continued without SSE
>capability rather than bomb out.
>
>If you've got the right headers but compiling on a non-SSE CPU you
>can certainly compile in the SSE support.  You just won't be able to
>use it on that system.

Ok, that all makes sense then.  An autoconf check ala:

checking if proper headers for SSE support exist... no

That would be ok I suppose, as the build environment really
should match the end-use environment IMHO for stable packaging,
however the CPU may differ at runtime, so the above should be ok.



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