Show-message function got error: Thread 1:EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)

Show-message function got error: Thread 1:EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)

following is the function.

-(void)showMeg:(NSString *)str { dispatch_sync(dispatch_get_main_queue(), ^{ [[[Memo1 textStorage] mutableString]appendString:[NSString stringWithFormat:@"%@", str]]; [Memo1 scrollRangeToVisible:NSMakeRange(Memo1.string.length, 0)];//auto scroll down }); }

I called it in other .m file like the following.

-(void)showMeg:(NSString *)str { dispatch_sync(dispatch_get_main_queue(), ^{ [[[Memo1 textStorage] mutableString]appendString:[NSString stringWithFormat:@"%@", str]]; [Memo1 scrollRangeToVisible:NSMakeRange(Memo1.string.length, 0)];//auto scroll down }); }

Sorry, the second section was copied the same code. The following is what I actually called.

Show-message function got error: Thread 1:EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
 
 
Q