Gives the list of used disks drivers.
Role: Gives the list of the letters currently used to mapp a disk. This
call is only usefull on Windows platforms, and thus will generate systematically
a CATLibSuccess return code and will return an empty array on Unix.
This function is used in C++ code.
Parameters:
iBufferSize
Size of the buffer .
iBuffer
The buffer will be filled with a character array containing contiguous
strings separated by NULL characters. The end of the array is marked by two
NULL characters.
oLen
Pointer to contain the length of the array filled. If this parameter
is NULL, the default, this information is not given.