[FFmpeg-devel] [PATCH] configure: disallow OpenCL with shared libs

[James Almer]

On 12/08/14 8:13 PM, Michael Niedermayer wrote:
> On Tue, Aug 12, 2014 at 07:31:58PM -0300, James Almer wrote:
>> On 11/08/14 11:33 PM, Michael Niedermayer wrote:
>>> Its API is marked as experimental, we should not export experimental API
>>> from shared libs
>>>
>>> Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
>>> ---
>>>  configure |    4 +++-
>>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/configure b/configure
>>> index 0ac6132..84d308e 100755
>>> --- a/configure
>>> +++ b/configure
>>> @@ -4861,7 +4861,9 @@ enabled opencl            && { check_lib2 OpenCL/cl.h clEnqueueNDRangeKernel -Wl
>>>                                 die "ERROR: opencl not found"; } &&
>>>                               { check_cpp_condition "OpenCL/cl.h" "defined(CL_VERSION_1_2)" ||
>>>                                 check_cpp_condition "CL/cl.h" "defined(CL_VERSION_1_2)" ||
>>> -                               die "ERROR: opencl must be installed and version must be 1.2 or compatible"; }
>>> +                               die "ERROR: opencl must be installed and version must be 1.2 or compatible"; } &&
>>> +                             { enabled shared &&
>>> +                               die "ERROR OpenCL API is experimental and not safe to be used with shared libs"; }
>>>  enabled opengl            && { check_lib GL/glx.h glXGetProcAddress "-lGL" ||
>>>                                 check_lib2 windows.h wglGetProcAddress "-lopengl32 -lgdi32" ||
>>>                                 check_lib2 OpenGL/gl3.h glGetError "-Wl,-framework,OpenGL" ||
>>>
>>
>> The API hasn't been touched in several months and is functional, and considering 
>> distros already link to opencl if available in previous ffmpeg releases, i don't 
>> know if removing the feature like this is a good idea.
>> Of course they can just remove this check and keep using opencl if they want to, 
>> but that's besides the point.
>>
>> Maybe a warning instead?
> 
> The question is if people intend to change the API and IIRC its
> design makes it hard to make changes without breaking ABI

OpenCL maintainers should probably chime in at this point. CCing Wei Gao then.

> 
> i can add a warning if preferred but i think we either should
> choose to support the ABI/API until the next bump which wouldnt
> need a warning or not support it in which case we probably should
> disable it hard for shared libs or put a warning in the release notes
> where its hard to miss

A warning in release notes and in the configure script is IMO preferable than 
disabling existing functionality, but i'm fine doing whatever causes the less 
headaches for everyone.

> 
> [...]
> 
> 
> 
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