1.invalid argument type 'void' to unary expression

1 @try{ 2         if (![mJQFMDB open]) { 3             NSLog(@"Could not open db."); 4             return NO; 5         }else { 6             NSArray *mLineInfoAry = responseObject[@"Data"]; 7             if(mLineInfoAry != nil && mLineInfoAry.count > 0) { 8                 for (NSDictionary *lineInfo in mLineInfoAry) { 9                     10                 }11             }12             return YES;13         }14     }@catch(NSException *ex) {15         [TExUtils uploadEx:ex];16     }@finally {17         [mFMDB close];18     }

该类继承父类，父类成员变量如下：

1 @interface BasicDataBase : NSObject {2     //成员变量3     @public4     FMDatabase *mFMDB;5     @public6     JQFMDB *mJQFMDB;7 }