This function can be called at any time to get the revision
level of the library. The version is encoded into an
unsigned integer and returned in the version argument.
A revision number is composed of two fields: a major number
and a minor number. Both can be extracted from the returned
argument using macros provided in the header file:
returns the major number encoded in v.
returns the minor number encoded in v.
The function returns whether or not it was successful.
A return value of PFMLIB_SUCCESS indicates success,
otherwise the value is the error code.
the argument is invalid, most likely a NULL pointer.