Re: [Starpu-devel] SOCL and ICD

[Vincent Danjean <Vincent.Danjean@imag.fr>]

Le 02/10/2012 15:29, Nathalie Furmento a écrit :
> On Oct 02, 15:07, Ludovic Courtès wrote:
>> If that libraries defines specific macros, or exports specific symbols,
>> ‘configure’ could check for them.

A macro is not really useful : ocl-icd installs a library (libOpenCL.so)
and a header (ocl_icd.h).
  However, the header provides some info required to compile a ICD but
the header is not useful to compile a program against libOpenCL.so.
The header can be installed and used whatever version of libOpenCL.so
is installed.
  So there is no point into adding macro and/or function declaration
into this header.

  To compile against libOpenCL.so, only the official Khronos OpenCL
headers are required. Of cause, we cannot (and want not) modify them.
Moreover, the compiled program should be able to run with whatever
libOpenCL.so will be found at runtime.

  I had the same problem when adding ICD support in POCL. So I agree
that something must be done. I see several things :
- add a symbol in the library. For example a
  char* ocl_icd_version()
  Pro : can be used to check the library
  Cons : easy to write an OpenCL that wont run with another libOpenCL.so
    (if it use unconditionally this symbol)
- add this function (or another) but its address must be obtain
  through clGetExtensionFunctionAddress
  Pro : same as before
  Pro : do not modify the ABI
  Cons : not really following the spec

I think the second one is better. What do you think ?

  Regards,
    Vincent

> That could be a solution.
> 
> Nathalie
> 


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Vincent Danjean          Adresse: Laboratoire d'Informatique de Grenoble
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