Two questions about cudaMemcpyToArray

[Blake]

The explanation of cudaMemcpyToArray in the CUDA reference manual fails to answer a couple of important questions. I’ve copied and pasted it here:

cudaMemcpyToArray- copies data between host and device

SYNOPSIS

cudaError_t cudaMemcpyToArray(struct cudaArray* dstArray, size_t dstX, size_t dstY, const void*

src, size_t count, enum cudaMemcpyKind kind)

cudaError_t cudaMemcpyToArrayAsync(struct cudaArray* dstArray, size_t dstX, size_t dstY, const

void* src, size_t count, enum cudaMemcpyKind kind, cudaStream_t stream)

DESCRIPTION

Copies count bytes from the memory area pointed to by src to the CUDA array dstArray starting at the

upper left corner (dstX, dstY), where kind is one of cudaMemcpyHostToHost, [b]cudaMemcpyHost-

ToDevice[/b], cudaMemcpyDeviceToHost, or cudaMemcpyDeviceToDevice, and specifies the direction

of the copy.

cudaMemcpyToArrayAsync() is asynchronous and can optionally be associated to a stream by passing

a non-zero stream argument. It only works on page-locked host memory and returns an error if a pointer to

pageable memory is passed as input.

My questions are:

1. What are the units of dstX and dstY (I think that dstX is in bytes and dstY is just the row number, but I would appreciate it if someone could confirm that).

2. I think that the copy happens in row major order. Is that correct?

In other words, a call to cudaMemcpyToArray will copy count bytes into row dstY, starting dstX bytes from the beginning of the row. Is this correct?

Thanks!