Retrieves data from a memory buffer as a binary string.
_WinAPI_GetBufferData($pBuffer[, $iLength])
| $pBuffer | Pointer to the memory buffer. |
| $iLength | [optional] Size of the data to retrieve (default: entire buffer). |
| Success: | Binary string containing the buffer data. |
| Failure: | 0, sets @error to 1 (invalid buffer). |