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6.21 acc_present_or_create – If the data is not present on the device, allocate device memory and map it to host memory.

Description

This function tests if the host data specified by a and of length len is present or not. If it is not present, then device memory will be allocated and mapped to host memory. In C/C++, the device address of the newly allocated device memory is returned.

In Fortran, two (2) forms are supported. In the first form, a specifies a contiguous array section. The second form a specifies a variable or array element and len specifies the length in bytes.

Note that acc_present_or_create and acc_pcreate exist for backward compatibility with OpenACC 2.0; use acc_create – Allocate device memory and map it to host memory. instead.

C/C++:
Prototype:void *acc_present_or_create(h_void *a, size_t len)
Prototype:void *acc_pcreate(h_void *a, size_t len)
Fortran:
Interface:subroutine acc_present_or_create(a)
type, dimension(:[,:]...) :: a
Interface:subroutine acc_present_or_create(a, len)
type, dimension(:[,:]...) :: a
integer len
Interface:subroutine acc_pcreate(a)
type, dimension(:[,:]...) :: a
Interface:subroutine acc_pcreate(a, len)
type, dimension(:[,:]...) :: a
integer len
Reference:

OpenACC specification v2.6, section 3.2.21.