possible bug when using omp_set_num_threads with -fno-underscoring

[Andreas Breslau]

Hi all,

I have found something in gfortran which is at least surprising, more
likely a bug.

Using -fno-underscoring with omp_set_num_threads() followed by a !$OMP
PARALLEL region leads to a Segmentation fault.
(Without a following PARALLEL region it works but is useless... ;-) )
As a work around the trailing "_" can be inserted manually:
omp_set_num_threads_()

Below is a minimal example producing the "surprise".

After compilation with "gfortran -fopenmp -o bsp bsp.f90" the program
works as expected,
after compilation with "gfortran -fopenmp -fno-underscoring -o bsp
bsp.f90" it segfaults.

This happens in the versions 4.8.1 and 4.9.1


Did I miss something or is this unintended?


Greetings from Cologne, Germany
Cheers Andreas Breslau



------------------------------------------------------------
! bsp.f90
program bsp
  use omp_lib
  implicit none

  !$OMP PARALLEL
  !$ IF( OMP_GET_THREAD_NUM() .EQ. 0 ) WRITE(*,*) 'Using OpenMP with',
OMP_GET_NUM_THREADS(), 'threads.'
  !$OMP END PARALLEL

  !$ call omp_set_num_threads(4)

  !$OMP PARALLEL
  !$ IF( OMP_GET_THREAD_NUM() .EQ. 0 ) WRITE(*,*) 'Using OpenMP with',
OMP_GET_NUM_THREADS(), 'threads.'
  !$OMP END PARALLEL

end program bsp