[Openmp-dev] _OPENMP undefined unless compiling with -fopenmp=libiomp5

[Schlottke-Lakemper, Michael]

Hi Jonas,

Thanks again, your proposed solution fixed it for me.

Michael

> On 20 Jul 2015, at 11:13 , Hahnfeld, Jonas <Hahnfeld at itc.rwth-aachen.de> wrote:
> 
> Hi Michael,
> 
> correct, it must be passed to LLVM/clang!
> 
> Jonas
> 
> From: Schlottke-Lakemper, Michael 
> Sent: Monday, July 20, 2015 11:09 AM
> To: Hahnfeld, Jonas; openmp-dev at dcs-maillist2.engr.illinois.edu
> Subject: RE: [Openmp-dev] _OPENMP undefined unless compiling with
> -fopenmp=libiomp5
> 
> Hi Jonas, 
> 
> Thank you for the fast answer. Just to be clear: the
> -DCLANG_DEFAULT_OPENMP_RUNTIME=libomp flag is specified at configuration
> time to LLVM, not to the libomp runtime, am I correct? 
> 
> Yours 
> 
> Michael 
> 
> 
> -------- Original message --------
> From: "Hahnfeld, Jonas" <Hahnfeld at itc.rwth-aachen.de> 
> Date: 20/07/2015 09:50 (GMT+01:00) 
> To: "Schlottke-Lakemper, Michael" <m.schlottke-lakemper at aia.rwth-aachen.de>,
> openmp-dev at dcs-maillist2.engr.illinois.edu 
> Subject: RE: [Openmp-dev] _OPENMP undefined unless compiling with
> -fopenmp=libiomp5 
> Hi Michael,
> 
> there is a CMake configuration "-DCLANG_DEFAULT_OPENMP_RUNTIME=libomp" which
> one can use to make "-fopenmp" work by default.
> And from my information there are plans to make it the default when this
> library is fully integrated into the LLVM build system. This is currently
> work in progress...
> 
> Greetings,
> Jonas
> 
> From: openmp-dev-bounces at cs.uiuc.edu [mailto:openmp-dev-bounces at cs.uiuc.edu]
> On Behalf Of Schlottke-Lakemper, Michael
> Sent: Sunday, July 19, 2015 7:58 AM
> To: openmp-dev at dcs-maillist2.engr.illinois.edu
> Subject: [Openmp-dev] _OPENMP undefined unless compiling with
> -fopenmp=libiomp5
> 
> Hi everyone, 
> 
> Right now we have to provide not just “-fopenmp” but “-fopenmp=libiomp5” if
> we want full support for OpenMP when compiling on Linux (without the
> explicit library, _OPENMP is undefined and there is only a single thread).
> Are there plans to drop this requirement and support plain “-fopenmp”? I’m
> asking since it would make things much easier for our users when
> transitioning from gcc to clang.
> 
> Thanks a lot!
> 
> Michael
> 
> --
> Michael Schlottke-Lakemper
> 
> SimLab Highly Scalable Fluids & Solids Engineering
> Jülich Aachen Research Alliance (JARA-HPC)
> RWTH Aachen University
> Wüllnerstraße 5a
> 52062 Aachen
> Germany
> 
> Phone: +49 (241) 80 95188
> Fax: +49 (241) 80 92257
> Mail: m.schlottke-lakemper at aia.rwth-aachen.de
> Web: http://www.jara.org/jara-hpc