警告:算术中使用的类型为"void *"的指针 [英] warning: pointer of type ‘void *’ used in arithmetic

问题描述

我正在从内存映射中读写寄存器，如下所示:

I am writing and reading registers from a memory map, like this:

//READ
return *((volatile uint32_t *) ( map + offset ));

//WRITE
*((volatile uint32_t *) ( map + offset )) = value;

但是编译器给我这样的警告:

However the compiler gives me warnings like this:

warning: pointer of type ‘void *’ used in arithmetic [-Wpointer-arith]

如何更改代码以删除警告?我正在使用C ++和Linux.

How can I change my code to remove the warnings? I am using C++ and Linux.

推荐答案

由于void*是指向未知类型的指针，因此您无法对其进行指针算术运算，因为编译器将不知道所指向的内容有多大到是.

Since void* is a pointer to an unknown type you can't do pointer arithmetic on it, as the compiler wouldn't know how big the thing pointed to is.

您最好的选择是将map强制转换为一个字节宽的类型，然后进行算术运算.您可以为此使用 uint8_t :

Your best bet is to cast map to a type that is a byte wide and then do the arithmetic. You can use uint8_t for this:

//READ
return *((volatile uint32_t *) ( ((uint8_t*)map) + offset ));

//WRITE
*((volatile uint32_t *) ( ((uint8_t*)map)+ offset )) = value;

这篇关于警告:算术中使用的类型为"void *"的指针的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！