PROGRAM lock    
      INTEGER*8 LOCKA, LOCKB
      INTEGER NTHREADS, TID, I, OMP_GET_NUM_THREADS, OMP_GET_THREAD_NUM
      PARAMETER (N=1000000)
      REAL A(N), B(N), PI, DELTA
      PARAMETER (PI=3.1415926535)
      PARAMETER (DELTA=.01415926535)
 
      CALL OMP_INIT_LOCK(LOCKA)
      CALL OMP_INIT_LOCK(LOCKB)
 
!$OMP PARALLEL SHARED(A, B, NTHREADS, LOCKA, LOCKB) PRIVATE(TID)
 
      TID = OMP_GET_THREAD_NUM()
!$OMP MASTER
      NTHREADS = OMP_GET_NUM_THREADS()
      PRINT*, 'Number of threads = ', NTHREADS
!$OMP END MASTER
      PRINT *, 'Thread', TID, 'starting...'
!$OMP BARRIER
!$OMP SECTIONS
!$OMP SECTION
  PRINT *, 'Thread',TID,' initializing A()'
  CALL OMP_SET_LOCK(LOCKA)
      DO I = 1, N
         A(I) = I * DELTA
      ENDDO
  CALL OMP_SET_LOCK(LOCKB)
  PRINT *, 'Thread',TID,' adding A() to B()'
      DO I = 1, N
         B(I) = B(I) + A(I)
      ENDDO
   CALL OMP_UNSET_LOCK(LOCKB)
   CALL OMP_UNSET_LOCK(LOCKA)

!$OMP SECTION

   PRINT *, 'Thread',TID,' initializing B()'
   CALL OMP_SET_LOCK(LOCKB)
      DO I = 1, N
         B(I) = I * PI
      ENDDO
   CALL OMP_SET_LOCK(LOCKA)
   PRINT *, 'Thread',TID,' adding B() toA()'
      DO I = 1, N
         A(I) = A(I) + B(I)
      ENDDO
   CALL OMP_UNSET_LOCK(LOCKA)
   CALL OMP_UNSET_LOCK(LOCKB)
 
!$OMP END SECTIONS NOWAIT
 
      PRINT *, 'Thread',TID,' done.'
 
!$OMP END PARALLEL
 
      END