[Proj] threadsafety and PROJ.4 - the projCtx API Update

[Frank Warmerdam]

Greg Troxel wrote:
>   Is there a reason for not using thread-local state, as is done for
>   errno?
> 
> My impression is that not all platforms that support threads have solid
> tls support.
> But that may not be a good reason not to use the standard feature.

Glynn / Greg,

I did a review of thread local variable support on different platforms
several years ago and came to the conclusion that it was not available
cross platform.   I'm assuming this is still the case.  So this is
intended to be a cross platform solution.

I would add that this also gives the opportunity for some other future
facilities like context specific loggers that might be mildly useful.

Best regards,
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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