c - 将 void * 指针变量从 unsigned int 类型转换为 uint32 时出现编译时错误

Question

我试图将 void * 类型的值转换为 uint32 但编译后出现错误:

error: cast from pointer to integer of different size

Answer 1

C 标准所说的是这样的，C11 6.3.2.3/6:

Any pointer type may be converted to an integer type. Except as previously specified, the result is implementation-defined. If the result cannot be represented in the integer type, the behavior is undefined. The result need not be in the range of values of any integer type.

这意味着由编译器来指定给定系统上将发生什么。显然，您的特定编译器认为结果无法表示，因此会抛出诊断消息。

您应该做的是转换为uintptr_t。该类型保证足够大以包含对象指针值。