3. gpmi - errors
3. no bools, yes ints
Gpmi avoids using bool to return a status of an operation (success or
failure). Rather, such routines returns an int. When such a function
succeed, it will return 0, otherwise a negative number for internal
(gpmi) errors or a positive number for system errors.
3. error codes
Error codes are listed in gpmi/error.h. Gpmi uses negative
numbers from -34000 to 34999 to help the application that
using a similar error reporting to avoid colliding error
codes.