我如何从object_getIvar(self，myIntVar)获取int值，因为它返回了一个指针 [英] How do I get the int value from object_getIvar(self, myIntVar) as it returns a pointer

问题描述

如果object_getIvar中的变量是基本数据类型(例如float，int，bool)，那么根据文档，该函数返回指针(id)时如何获取值.我已经尝试过将类型转换为int *，但是当我尝试将其转换为NSLog时，出现关于不兼容的指针类型的错误.

if the variable in object_getIvar is a basic data type (eg. float, int, bool) how do I get the value as the function returns a pointer (id) according to the documentation. I've tried casting to an int, int* but when I try to get that to NSLog, I get error about an incompatible pointer type.

推荐答案

获取:

myFloat = 2.34f;

float myFloatValue;
object_getInstanceVariable(self, "myFloat", (void*)&myFloatValue);

NSLog(@"%f", myFloatValue);

输出:

2.340000

2.340000

设置:

float newValue = 2.34f;
unsigned int addr = (unsigned int)&newValue;

object_setInstanceVariable(self, "myFloat", *(float**)addr);

NSLog(@"%f", myFloat);

输出:

2.340000

2.340000

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