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

[highgod0401]

highgod0401

From: James Almer
Date: 2014-08-13 07:28
To: FFmpeg development discussions and patches
CC: highgod0401; weigao
Subject: Re: [FFmpeg-devel] [PATCH] configure: disallow OpenCL with shared libs
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.

Hi

Warning is OK for me.

Thanks

Best regards

> 
> [...]
> 
> 
> 
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>