acc_present_or_create– If the data is not present on the device, allocate device memory and map it to host memory.
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.
acc_pcreate exist for
backward compatibility with OpenACC 2.0; use
acc_create – Allocate device memory and map it to host memory. instead.
OpenACC specification v2.6, section 3.2.21.