Unlock a read/write GLOP that was previously locked with a call to FNC_GLOP_Lock.
FNC_GLOP_Unlock returns an integer with the following possible values.
| Value | Meaning |
|---|---|
| 0 | Unlock was successful. |
| -1 | The index is not valid or the entry is not mapped. |
| -2 | There was no lock. |