Use the SHARED clause on the PARALLEL, PARALLEL DO, and PARALLEL SECTIONS directives to make variables shared among all the threads in a team.
In the following example, the variables X and NPOINTS are shared among all the threads in the team:
!$OMP PARALLEL DEFAULT(PRIVATE),SHARED(X,NPOINTS)
IAM = OMP_GET_THREAD_NUM()
NP = OMP_GET_NUM_THREADS()
IPOINTS = NPOINTS/NP
!$OMP END PARALLEL