从Objective-C中的实例十六进制获取类 [英] Get class from instance hex in Objective-C

问题描述

当在调试器中看到实例变量的地址时，如何通过输入给定的内存地址来获取类？

When seeing an instance variable's address in the debugger, how can one get the class by entering in the given memory address?

我知道相反（获取可以在调试器中使用 p someObjectInstance 或 NSLog（@％p，someObjectInstance）; 从代码中。有没有类似的方法来反过来这样做？

I know that the opposite (getting the address from an instance) is possible with p someObjectInstance in the debugger or NSLog(@"%p", someObjectInstance); from within the code. Is there a similar way to do this the other way around?

推荐答案

你要求的是非常不安全的。访问一个未知的内存位置通常是一个坏主意，但因为你问：

What you are asking for is VERY unsafe. Accessing an unknown memory location is generally a bad idea, but since you asked:

编辑：如果在 gdb 内或 lldb ，您可以执行以下操作：

If inside gdb or lldb, you can do the following:

po [(id)(0xDEADBEEF) class]

但是，如果从代码运行，请使用以下内容;

If running from code, however, use the following;

NSString *input = @"0xFAFAFA";

unsigned address = UINT_MAX; // or UINT_MAX
[[NSScanner scannerWithString:input] scanHexInt:&address];

if (address == UINT_MAX)
{
    // couldn't parse input...
    NSLog(@"failed to parse input");
    return 0;
}

void *asRawPointer = (void *) (intptr_t) address;
id value = (__bridge id) asRawPointer;

// now do something with 'value'
NSLog(@"%@", [value class]);

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