Re: gfortran, OpenMP and static linking

[Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>]

Harald,

On Sat, 03 Apr 2021 23:24:52 +0200
Bernhard Reutner-Fischer <rep.dot.nop@gmail.com> wrote:

> On 3 April 2021 20:55:39 CEST, Harald Anlauf via Fortran <fortran@gcc.gnu.org> wrote:
> >Dear all,
> >
> >is there a reason that one should not be able to statically link a
> >Fortran binary that has been compiled with -fopenmp?  
> 
> Maybe Jakub knows more on this.
> 
> Not sure if static linking with glibc is still discouraged (it was, at least in former times) or if thread cancellation still is supposed to work in a pure static build.

You can try to get away with linking libpthread in like below.
However, glibc is (still) not supposed to be linked statically (don't
ask me, i didn't write it).
HTH,

$ cat omp.f90 
use omp_lib
!$omp parallel
  write(*,*) "thread ", omp_get_thread_num()
!$omp end parallel
end
$ gfortran -o omp -fopenmp omp.f90 -static -Wl,--whole-archive -lpthread -Wl,--no-whole-archive && OMP_NUM_THREADS=2 ./omp
/usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/10/libgomp.a(target.o): in function `gomp_target_init':
(.text+0x358): warning: Using 'dlopen' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
 thread            0
 thread            1