使用memcpy（）将一个结构复制到另一个结构 [英] use memcpy() to copy one structure to another

问题描述

大家好。


我可以这样做来复制struct b中struct a的内容吗

struct myStruct a，b， * aptr，* bptr;

aptr = a;

bptr = b;

做一些事情来初始化结构的内容a

memcpy（bptr，aptr，sizeof（myStruct））;


或者假设使用内存并不是一个好主意

by my结构是连续的吗？

我应该逐场进行。


Kev。

Hi all.

Can I do this to duplicate the contents of struct a in struct b

struct myStruct a, b, *aptr, *bptr;
aptr = a;
bptr = b;
Do something to initialize contents of structure a
memcpy(bptr, aptr, sizeof(myStruct));

Or is not not a good idea to assume the memory used
by my structure is contiguous ?
should I instead do it field by field.

Kev.

推荐答案

Sourcerer写道：

Sourcerer wrote:

大家好。

我可以这样做来复制struct b中struct a的内容

struct myStruct a，b，* aptr，* bptr;
aptr = a;


非法。你的意思是& a？

bptr = b;


Ditto& b。

做一些事情来初始化结构的内容a
memcpy（bptr，aptr，sizeof（myStruct））;

或者假设我的结构使用的内存是连续的并不是一个好主意？


它可能有差距，但sizeof将涵盖所有。但是为什么不用


memcpy（bptr，aptr，sizeof（* bptr））;

如果你使用memcpy设置了
？

我应该逐字逐句。

Hi all.

Can I do this to duplicate the contents of struct a in struct b

struct myStruct a, b, *aptr, *bptr;
aptr = a;
Illegal. Did you mean &a?
bptr = b;
Ditto &b.
Do something to initialize contents of structure a
memcpy(bptr, aptr, sizeof(myStruct));

Or is not not a good idea to assume the memory used
by my structure is contiguous ?
It may have gaps, but sizeof will cover them all. But why not

memcpy( bptr, aptr, sizeof (*bptr) );

if you''re set on using memcpy?
should I instead do it field by field.

$ b $有什么问题ba = b;


？


-

Chris" electric hedgehog" Dollin

C常见问题解答： http://www.faqs.org/faqs/by-newsgrou...mp.lang.c.html

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Sourcerer< no **** @ donteventhinkaboutspammingme.xyz>写道：

Sourcerer <no****@donteventhinkaboutspammingme.xyz> writes:

大家好。

我可以这样做来复制struct b中struct a的内容吗
struct myStruct a ，b，* aptr，* bptr;
aptr = a;
bptr = b;
做一些事情来初始化结构的内容a
memcpy（bptr，aptr，sizeof（myStruct） ））;

Hi all.

Can I do this to duplicate the contents of struct a in struct b

struct myStruct a, b, *aptr, *bptr;
aptr = a;
bptr = b;
Do something to initialize contents of structure a
memcpy(bptr, aptr, sizeof(myStruct));

memcpy（& b，& a，sizeof b）;或简单地b = a;

memcpy (&b, &a, sizeof b); or simply b = a;

2004年6月15日星期二14:13:22 +0100，Chris Dollin< ke ** @ hpl.hp.com> < br $>
写道：

On Tue, 15 Jun 2004 14:13:22 +0100, Chris Dollin <ke**@hpl.hp.com>
wrote:

Sourcerer写道：

Sourcerer wrote:

大家好。

我可以做吗？这是复制struct b中struct a的内容
struct myStruct a，b，* aptr，* bptr;
aptr = a;

Hi all.

Can I do this to duplicate the contents of struct a in struct b

struct myStruct a, b, *aptr, *bptr;
aptr = a;

非法。你的意思是& a？

Illegal. Did you mean &a?

bptr = b;

bptr = b;

同上& b。

Ditto &b.

做一些事情来初始化结构的内容a
memcpy（bptr，aptr，sizeof（myStruct））;

或者假设使用的内存不是一个好主意
我的结构是连续的吗？

Do something to initialize contents of structure a
memcpy(bptr, aptr, sizeof(myStruct));

Or is not not a good idea to assume the memory used
by my structure is contiguous ?

它可能有差距，但sizeof将覆盖它们。但是为什么不用memcpy（bptr，aptr，sizeof（* bptr））;

如果你开始使用memcpy？

It may have gaps, but sizeof will cover them all. But why not

memcpy( bptr, aptr, sizeof (*bptr) );

if you''re set on using memcpy?

我应该逐个字段地进行。

should I instead do it field by field.

a = b;
？

哇！那很快。


我没有意识到a = b会这样做。


所以，我可以有


struct mystruct

{

char str [50];

}


struct mystruct a，b;

sprintf（a.str，" Testing 123"）;

b = a;


然后b.str还包含Testing 123。 ？

Wow ! that was fast.

I hadn''t realized a = b would do it.

so, I could have

struct mystruct
{
char str[50];
}

struct mystruct a, b;
sprintf(a.str, "Testing 123");
b = a;

and then b.str would also contain "Testing 123" ?

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