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.