macOS Problems with mac os lion and openmp

[jalonso]

Hello all,

I am getting my way around openmp and I get the following error when I compile using either ifort or gfortran

Undefined symbols for architecture x86_64:
"_MAIN__", referenced from:
_main in for_main.o
ld: symbol(s) not found for architecture x86_64
sh_mxvp.sh: line 5: 1021 Illegal instruction: 4 ./myprog

This is the program

SUBROUTINE mxvp(m,n,a,b,c)
IMPLICIT NONE
INTEGER, INTENT(IN) :: m,n
REAL, INTENT(INOUT) :: a(m)
REAL, INTENT(IN) :: b(m,n),c(n)
INTEGER :: i,j
!$OMP PARALLEL DO DEFAULT(NONE) &
!$OMP SHARED(m,n,a,b,c) PRIVATE(i,j)
DO i=1,m
a(i)=0.0
DO j=1,n
a(i)=a(i)+b(i,j)*c(j)
END DO
END DO
!$OMP END PARALLEL DO
END SUBROUTINE mxvp

And these are the .sh files

gfortran -fopenmp -c mxvp.f90
gfortran -fopenmp -o myprog mxvp.o

./myprog

ifort -fopenmp -c mxvp.f90
ifort -fopenmp -o myprog mxvp.o

./myprog

I already tried to add -m64 and/or -arch x86_64

Thank you all in advance