从const对< const unsigned char *，size_t> *转换为constpair< unsigned char *，size_t> * [英] Casting from const pair<const unsigned char*, size_t>* to constpair<unsigned char*, size_t>*

问题描述

是否可以进行C ++ - 来自

const pair< const unsigned char *，size_t> *

to

const pair< unsigned char *，size_t> *

？


Alex Vinokur

解决方案

2008-10-12 13:16，Alex Vinokur写道：

是否可以进行C ++ - 从

const对< const unsigned char *，size_t> *

转换为

const pair< unsigned char *，size_t> *

？

const_cast可能有效，但我认为这不算什么就可以了。

constness，你应该使用reinterpret_cast。


-

Erik Wikstr ?? m

10月12日，7：16 * pm， Alex Vinokur< ale ... @ users.sourceforge.netwrote：

是否可以做C ++ - 来自

const pair< const unsigned char *，size_t> *

to

const pair< unsigned char *，size_t> *

？

const pair< const unsigned char *，size_t> * p1 = 0;

const pair< ; unsigned char *，size_t> * p2 =

reinterpret_cast< const pair< unsigned char *，size_t> *>（p1）;


但reinterpre_cast应该尽可能避免。

*实际上*，我想你可以这样做：


char * s = const_cast< char *> （p1-> first）;


或者你能告诉我你所处的情景吗？


-

最好的问候

Barry

10月12日，2：22 * pm，Barry< dhb2 ... @ gmail.comwrote：

10月12日，7：16 * pm，Alex Vinokur< ale ... @ users.sourceforge.netwrote：

是否可以进行C ++ - 来自

const pair< const unsigned char *，size_t> *

to

const pair< unsigned char *，size_t> *

？

* const pair< const unsigned char *，size_t> * p1 = 0;

* const pair< unsigned char *，size_t> * p2 =

* * * * reinterpret_cast< const pair< unsigned char *，size_t> *>（p1）;


但应避免使用reinterpre_cast如果可能的话。

*实际上*，我想你可以这样做：


* char * s = const_cast< char *>（p1 - >第一个）;


或者你能告诉我你的情景吗？

我有函数foo1（ const pair< unsigned char *，size_t> * p）;

我还需要函数foo2（const pair< const unsigned char *，size_t> *

p）与foo1（）相同的东西。


目前

void foo2（const pair< const unsigned char *，size_t> * p）

{

//我想在这里使用C ++ - 样式转换

const pair< unsigned char *，size_t> * p1 =（const pair< unsigned

char *，size_t> *）p;

foo1（p1）;

}


Alex Vinokur

Hi,

Is it possible to do C++-casting from
const pair<const unsigned char*, size_t>*
to
const pair<unsigned char*, size_t>*
?

Alex Vinokur

解决方案

On 2008-10-12 13:16, Alex Vinokur wrote:

Hi,

Is it possible to do C++-casting from
const pair<const unsigned char*, size_t>*
to
const pair<unsigned char*, size_t>*
?

const_cast might work, but I don''t think this counts as casting away
constness, you should probably use reinterpret_cast.

--
Erik Wikstr??m

On Oct 12, 7:16*pm, Alex Vinokur <[e-mail]:

Hi,

Is it possible to do C++-casting from
const pair<const unsigned char*, size_t>*
to
const pair<unsigned char*, size_t>*
?

const pair<const unsigned char*, size_t>* p1 = 0;
const pair<unsigned char*, size_t>* p2 =
reinterpret_cast<const pair<unsigned char*, size_t>*>(p1);

but reinterpre_cast should be avoided if possible.
*Practically*, I wonder you can just do it this way:

char* s = const_cast<char*>(p1->first);

Or can you tell me the scenario you are in?

--
Best Regards
Barry

On Oct 12, 2:22*pm, Barry <[e-mail]:

On Oct 12, 7:16*pm, Alex Vinokur <[e-mail]:

Hi,

Is it possible to do C++-casting from
const pair<const unsigned char*, size_t>*
to
const pair<unsigned char*, size_t>*
?

* const pair<const unsigned char*, size_t>* p1 = 0;
* const pair<unsigned char*, size_t>* p2 =
* * * * reinterpret_cast<const pair<unsigned char*, size_t>*>(p1);

but reinterpre_cast should be avoided if possible.
*Practically*, I wonder you can just do it this way:

* char* s = const_cast<char*>(p1->first);

Or can you tell me the scenario you are in?

I have function foo1 (const pair<unsigned char*, size_t>* p);
I need also function foo2 (const pair<const unsigned char*, size_t>*
p) that does the same thing as foo1().

Currently
void foo2 (const pair<const unsigned char*, size_t>* p)
{
// I would like to use here C++-style casting
const pair<unsigned char*, size_t>* p1 = ( const pair<unsigned
char*, size_t>* ) p;
foo1(p1);
}

Alex Vinokur

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