使用格式大致如下：
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-相關命令"
? ? //需要操作的代碼
#pragma clang diagnostic pop
栗子1：忽略棄用的警告?
//方法棄用告警? ?
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
? ? UIAlertView *alertViewTmp = [[UIAlertView alloc]initWithTitle:@"" message:@"" delegate:nil cancelButtonTitle:@"" otherButtonTitles:@"", nil];
? ? [alertViewTmp show];
#pragma clang diagnostic pop
栗子2：忽略不兼容指針類型?
//? 不兼容指針類型
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wincompatible-pointer-types"
? ? //
#pragma clang diagnostic pop
栗子3：循環引用?
break the retain cycle.
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Warc-retain-cycles"
//? ? self.completionBlock = ^ {
//? ? ? ? ...
//? ? };
#pragma clang diagnostic pop
栗子4：未使用變量 ?
// 未使用變量?
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunused-variable"
? ? int a;
#pragma clang diagnostic pop
栗子5：未使用default ?
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wcovered-switch-default"
//? ? switch (style) {
//? ? ? ? case UITableViewCellStyleDefault:
//? ? ? ? case UITableViewCellStyleValue1:
//? ? ? ? case UITableViewCellStyleValue2:
//? ? ? ? case UITableViewCellStyleSubtitle:
//? ? ? ? ? ? // ...
//? ? ? ? default:
//? ? ? ? ? ? return;
//? ? }
#pragma clang diagnostic pop
