POV-Ray : Newsgroups : povray.unix : Some help needed : Re: Some help needed Server Time
28 Nov 2021 09:17:12 EST (-0500)
  Re: Some help needed  
From: William F Pokorny
Date: 19 May 2017 15:35:36
Message: <591f4908$1@news.povray.org>
On 05/19/2017 10:21 AM, William F Pokorny wrote:
> On 05/18/2017 02:25 PM, clipka wrote:
> 
> Still looking, but it might take a while to work around pkg-config.
> 
> The real reason for the usage isn't the version determination but rather 
>   updating the compile include and link libraries via updating the 
> environment variables CPPFLAGS and LIBS, respectively.
> 
> The commands:
> 
>   pkg-config --cflags OpenEXR
> 
> and
> 
>   pkg-config --libs OpenEXR
> 
> are used to get what those respective updates should be.
> 
> The Simple DirectMedia Layer needs this sort of update too. As part of 
> its package a built in command called "sdl-config" is provided which 
> works as a stand in for pkg-config. I've found no similar mechanism for 
> openexr.
> 
> I'm trying now to figure out where pkg-config gets its information with 
> the idea maybe we could duplicate the function it performs.
> 
> Interesting too - I'm not sure the usual configure include / library 
> overrides will work with openexr. The mechanism is certainly different 
> than the jpeg set up if it does.
> 
> Bill P.

Got back to this a while ago. The more I dig the more I think if the
pkg-config command and its infrastructure exists, it should be used first.

In fact for best reliability, the pkg-config mechanism should perhaps be 
used first for all our packages when available. The necessary .pc files 
exists for the Simple DirectMedia Layer library too it turns out.

Have to stop for now, but my plan for tomorrow is to hard code the 
compiler and linker flags to use for openexr when pkg-config is not 
found after some checking for headers, library version and a test compile.

This hard coded method will be exposed to breakage on changes the whole 
pkg-config system was and is aimed at solving, but it should mostly work 
and not be too bad to patch over time based upon openexr version should 
the need arise.

Bill P.


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