问：reinterpret_cast有未定义的行为？ [英] Q: reinterpret_cast with undefined behavior?

问题描述

我正在尝试确定系统的字节顺序如下：


int i = 1;

bool is_little = * reinterpret_cast< char *> （& i）！= 0;


但是现在我问自己，根据标准，这种reinterpret_cast的使用是否有效？
有效。 br />

谢谢！

-

jb


（rot13的回复地址，首先解读）

解决方案

签名字符或无符号字符？


ben

我试图确定该系统的字节序如下：

INT I = 1;
布尔is_little = *的reinterpret_cast <字符*> （& i）！= 0;

但是现在我问自己，如果使用reinterpret_cast有效，根据标准。

谢谢！
-
jb

（在rot13回复地址，先解读）

< BLOCKQUOTE>"本" <是****** @ hotmail.com>在留言中写道

news：42 ********************** @ news.optusnet.com.au

int i = 1;
bool is_little = * reinterpret_cast< char *> （& i）！= 0;

signed char或unsigned char？

在我的系统上签名，但为什么这很重要？我正在测试

0 ..

-

jb


（回复地址在rot13，首先解读）

" Jakob Bieling" < AR **************** @ rot13.com> skrev i en meddelelse

新闻：d4 ************* @ news.t-online.com ...

我试图确定系统的字节顺序如下：

int i = 1;
bool is_little = * reinterpret_cast< char *> （& i）！= 0;

但是现在我问自己，如果使用reinterpret_cast是有效的，
根据标准。

谢谢！
-
jb

（回复地址在rot13，先解读）

这完全有效 - 请继续。 char的签名是

在这方面无关紧要。


/ Peter

Hi,

I am trying to determine the endianness of the system as follows:

int i = 1;
bool is_little = *reinterpret_cast <char*> (&i) != 0;

But now I was asking myself, if this use of reinterpret_cast is
valid, according to the Standard.

thanks!
--
jb

(reply address in rot13, unscramble first)

解决方案

signed char or unsigned char?

ben

Hi,

I am trying to determine the endianness of the system as follows:

int i = 1;
bool is_little = *reinterpret_cast <char*> (&i) != 0;

But now I was asking myself, if this use of reinterpret_cast is
valid, according to the Standard.

thanks!
--
jb

(reply address in rot13, unscramble first)

"ben" <be******@hotmail.com> wrote in message
news:42**********************@news.optusnet.com.au

int i = 1;
bool is_little = *reinterpret_cast <char*> (&i) != 0;

signed char or unsigned char?

On my system signed, but why does this matter? I am testing against
0 ..
--
jb

(reply address in rot13, unscramble first)

"Jakob Bieling" <ar****************@rot13.com> skrev i en meddelelse
news:d4*************@news.t-online.com...

Hi,

I am trying to determine the endianness of the system as follows:

int i = 1;
bool is_little = *reinterpret_cast <char*> (&i) != 0;

But now I was asking myself, if this use of reinterpret_cast is valid,
according to the Standard.

thanks!
--
jb

(reply address in rot13, unscramble first)

This is perfectly valid - just go ahead. The signedness of char is
irrelevant in this respect.

/Peter

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