10.11. copyin Clause

The copyin clause is used to initialize threadprivate data upon entry to a parallel region. The value of the threadprivate variable in the primary thread is copied to the threadprivate variable of each other team member.

//%compiler: clang
//%cflags: -fopenmp

/*
* name: copyin.1
* type: C
*/
#include <stdlib.h>

float* work;
int size;
float tol;

#pragma omp threadprivate(work,size,tol)

void build()
{
  int i;
  work = (float*)malloc( sizeof(float)*size );
  for( i = 0; i < size; ++i ) work[i] = tol;
}

void copyin_example( float t, int n )
{
  tol = t;
  size = n;
  #pragma omp parallel copyin(tol,size)
  {
    build();
  }
}

!!%compiler: gfortran
!!%cflags: -fopenmp

! name: copyin.1
! type: F-fixed
      MODULE M
        REAL, POINTER, SAVE :: WORK(:)
        INTEGER :: SIZE
        REAL :: TOL
!$OMP   THREADPRIVATE(WORK,SIZE,TOL)
      END MODULE M

      SUBROUTINE COPYIN_EXAMPLE( T, N )
        USE M
        REAL :: T
        INTEGER :: N
        TOL = T
        SIZE = N
!$OMP   PARALLEL COPYIN(TOL,SIZE)
        CALL BUILD
!$OMP   END PARALLEL
      END SUBROUTINE COPYIN_EXAMPLE

      SUBROUTINE BUILD
        USE M
        ALLOCATE(WORK(SIZE))
        WORK = TOL
      END SUBROUTINE BUILD