83   if( pId->pMethods ){  in sqlite3OsClose()
84     pId->pMethods->xClose(pId);  in sqlite3OsClose()
85     pId->pMethods = 0;  in sqlite3OsClose()
90   return id->pMethods->xRead(id, pBuf, amt, offset);  in sqlite3OsRead()
94   return id->pMethods->xWrite(id, pBuf, amt, offset);  in sqlite3OsWrite()
97   return id->pMethods->xTruncate(id, size);  in sqlite3OsTruncate()
101   return flags ? id->pMethods->xSync(id, flags) : SQLITE_OK;  in sqlite3OsSync()
105   return id->pMethods->xFileSize(id, pSize);  in sqlite3OsFileSize()
110   return id->pMethods->xLock(id, lockType);  in sqlite3OsLock()
114   return id->pMethods->xUnlock(id, lockType);  in sqlite3OsUnlock()
118   return id->pMethods->xCheckReservedLock(id, pResOut);  in sqlite3OsCheckReservedLock()
130   if( id->pMethods==0 ) return SQLITE_NOTFOUND;  in sqlite3OsFileControl()
155   return id->pMethods->xFileControl(id, op, pArg);  in sqlite3OsFileControl()
158   if( id->pMethods ) (void)id->pMethods->xFileControl(id, op, pArg);  in sqlite3OsFileControlHint()
162   int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;  in sqlite3OsSectorSize()
166   if( NEVER(id->pMethods==0) ) return 0;  in sqlite3OsDeviceCharacteristics()
167   return id->pMethods->xDeviceCharacteristics(id);  in sqlite3OsDeviceCharacteristics()
171   return id->pMethods->xShmLock(id, offset, n, flags);  in sqlite3OsShmLock()
174   id->pMethods->xShmBarrier(id);  in sqlite3OsShmBarrier()
177   return id->pMethods->xShmUnmap(id, deleteFlag);  in sqlite3OsShmUnmap()
187   return id->pMethods->xShmMap(id, iPage, pgsz, bExtend, pp);  in sqlite3OsShmMap()
195   return id->pMethods->xFetch(id, iOff, iAmt, pp);  in sqlite3OsFetch()
198   return id->pMethods->xUnfetch(id, iOff, p);  in sqlite3OsUnfetch()
230   assert( rc==SQLITE_OK || pFile->pMethods==0 );  in sqlite3OsOpen()