將錯誤分配給錯誤的指針指針時的潛在空引用

Question

在*perror = error行中獲取此值。甚至當我在if (error)

- (BOOL)validate:(NSError **)perror password:(BOOL)password { 
    BOOL ret = YES; 

    NSMutableString * errorMessage = [@"" mutableCopy]; 

    ...other validation code 

    NSError * error = [NSError errorWithDomain:@"Profile" code:100 userInfo:dictionary]; 

    if (error) { 
     *perror = error; 
    } 

    return ret; 
} 

Answer 1

包裹它這有可能是perror可能是nil。警惕：

if (error && perror) { 
    *perror = error; 
}