What is the meaning of a double dot within a square bracket in C++

Question

In the file C:\Program Files (x86)\Windows Kits\8.1\Include\um\OleAuto.h, I found the following code that I do not know how to interpret:

WINOLEAUTAPI SafeArrayAccessData(_In_ SAFEARRAY * psa,
_Outptr_result_buffer_(_Inexpressible_(psa->cbElements * 
product(psa->rgsabound[0..psa->cDims-1]->cElements))) 
void HUGEP** ppvData);

Note the double period within the square bracket. Is that a new operator in C++?

Answer 1

It appears to be a SAL annotation used to tell the static analyzer that the size of the buffer is too complex to represent using ordinary annotations:

https://msdn.microsoft.com/en-us/library/jj159527.aspx

It doesn't have to contain valid syntax, but what it contains is probably meant to succinctly illustrate to a human reader how the size of the buffer could be calculated.

If I'm to interpret it myself, I'd guess it means what the following code would yield:

DWORD CalculateInexpressibleSafeArrayDataSize(SAFEARRAY * psa)
{
    DWORD cbSize = psa->cbElements;
    for (int i = 0; i < psa->cDims; i++) // product()
        cbSize *= psa->rgsabound[i]->cElements;
    return cbSize;
}