为什么英寸长INT＆QUOT;具有相同的大小和QUOT; INT＆QUOT;？此修改器的工作原理呢？ [英] Why "long int" has same size as "int"? Are this modifier works at all?

问题描述

埃姆..我种'的虽然这修饰符例如长 / 短扩展/减少创建变量时，分配的内存量，但是......

Ehm.. I kind' of though this modifiers like long / short expands / reduces amount of memory allocated when variable are created, but...

#include <stdio.h>

#define test_int int
#define long_int long int
#define long_long_int long long int

void main()
{
    printf("%i\n", sizeof (test_int)); //output 4
    printf("%i\n", sizeof (long_int)); //output 4. Why? wasn't I modified it's size?
    printf("%i\n", sizeof (long_long_int)); //output 8
}

对于未知的我的理由，它打印的一样大小的内部和长整型相同。
我用VC ++ 2010的前preSS版。
对不起，很难找到答案谷歌，它总是显示的长和 INT 为不同的类型。

For unknown for me reason, it prints like size of int and long int are same. I use vc++ 2010 express edition. Sorry, hard to find answer in google, it always shows long and int as separate types.

推荐答案

之所以MS选择让长即使是在64位系统32位的是，现有的Windows API，由于历史原因，使用 INT 和长对于类似的事情，并期望是，这个混合是第32位值（一些本可以追溯到时候的Windows是一个16位系统）。因此，为了使老code转化为新的64位架构，他们选择保留长 32位，这样，应用混合 INT 和长在不同的地方仍然编译。

The reason that MS choose to makelong 32 bits even on a 64-bit system is that the existing Windows API, for historical reasons use a mixture of int and long for similar things, and the expectation is that this is s 32-bit value (some of this goes back to times when Windows was a 16-bit system). So to make the conversion of old code to the new 64-bit architecture, they choose to keep long at 32 bits, so that applications mixing int and long in various places would still compile.

有什么在C ++标准，它决定了一个长应该比 INT 更大（可以肯定的ISN在大多数32位系统'T）。所有的标准说的是，短＆LT的大小= INT ＆LT; = 长 - 和短至少是16位，如果没有记错pssed为[不一定EX $ p $至少应为16位我觉得它提到的数值范围。

There is nothing in the C++ standard that dictates that a long should be bigger than int (it certainly isn't on most 32-bit systems). All the standard says is that the size of short <= int <= long - and that short is at least 16 bits, if memory serves [not necessarily expressed as "should be at least 16 bits", I think it mentions the range of values].

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