clGetDeviceIDs throws error instead of returning []

[bergey]

The docs for clGetDeviceIDs say

-- | Obtain the list of devices available on a platform. Returns the list if
-- the function is executed successfully. Otherwise it returns the empty list
-- if platform is not a valid platform or no OpenCL devices that matched
-- device_type were found.

The implementation calls whenSuccess, and throws CLError if no matching devices are found.

Should the implementation or the documentation be changed?

[zhensydow]

Sorry I have no time to check this. I'll check documentation ASAP