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3.7.7 omp_target_memcpy_rect – Copy a subvolume of data between devices ¶

Description:

This routine copies a subvolume of data from the device identified by device number src_device_num to device dst_device_num. The array has num_dims dimensions and each array element has a size of element_size bytes. The volume array specifies how many elements per dimension are copied. The full sizes of the destination and source arrays are given by the dst_dimensions and src_dimensions arguments, respectively. The offset per dimension to the first element to be copied is given by the dst_offset and src_offset arguments. The routine returns zero on success and non-zero otherwise.

The OpenMP specification only requires that num_dims up to three is supported. In order to find implementation-specific maximally supported number of dimensions, the routine returns this value when invoked with a null pointer to both the dst and src arguments. As GCC supports arbitrary dimensions, it returns INT_MAX.

The device-number arguments must be conforming device numbers, the src and dst must be either both null pointers or all of the following must be fulfilled: element_size and num_dims must be positive and the volume, offset and dimension arrays must have at least num_dims dimensions.

Running this routine in a target region is not supported except on the initial device.

C/C++

Prototype:	int omp_target_memcpy_rect(void *dst,
	const void *src,
	size_t element_size,
	int num_dims,
	const size_t *volume,
	const size_t *dst_offset,
	const size_t *src_offset,
	const size_t *dst_dimensions,
	const size_t *src_dimensions,
	int dst_device_num,
	int src_device_num)

Fortran:

Interface:	integer(c_int) function omp_target_memcpy_rect( &
	dst, src, element_size, num_dims, volume, &
	dst_offset, src_offset, dst_dimensions, &
	src_dimensions, dst_device_num, src_device_num) bind(C)
	use, intrinsic :: iso_c_binding, only: c_ptr, c_size_t, c_int
	type(c_ptr), value :: dst, src
	integer(c_size_t), value :: element_size, dst_offset, src_offset
	integer(c_size_t), value :: volume, dst_dimensions, src_dimensions
	integer(c_int), value :: num_dims, dst_device_num, src_device_num

See also:

omp_target_memcpy_rect_async – Copy a subvolume of data between devices asynchronously, omp_target_memcpy – Copy data between devices

Reference:

OpenMP specification v5.1, Section 3.8.6