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Re: [PATCH] Add DISABLE_COPY_AND_ASSIGN
- From: Pedro Alves <palves at redhat dot com>
- To: Yao Qi <qiyaoltc at gmail dot com>
- Cc: gdb-patches at sourceware dot org
- Date: Tue, 18 Jul 2017 16:38:34 +0100
- Subject: Re: [PATCH] Add DISABLE_COPY_AND_ASSIGN
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On 07/18/2017 04:13 PM, Yao Qi wrote:
> Pedro Alves <palves@redhat.com> writes:
>
>> Yes, please. I've been meaning to add something like this for a while.
>>
>> IMO, this could go in include/ansidecl.h, with a fallback version for
>> #if __cplusplus < C++11 that declares the methods without =delete (you
>> get a link error instead).
>>
>
> I thought about adding this into include/, but can't find the right
> file. I'll move the macro to include/ansidecl.h.
Thanks. Note that that file is maintained by gcc.
>
>>> /* Pull in gdb::unique_xmalloc_ptr. */
>>> #include "common/gdb_unique_ptr.h"
>>>
>>> +#define DISABLE_COPY_AND_ASSIGN(TYPE) \
>>> + TYPE (const TYPE&) = delete; \
>>> + void operator= (const TYPE &) = delete;
>>> +
>>
>> Should this have an intro comment?
>>
>
> I thought it is too simple to have a comment :) How about this?
>
> /* A macro to disable the copy constructor and assignment operator.
> When building with C++ 11, explicitly delete these methods.
> Otherwise, place this macro in the private: declarations of a class. */
How about this tweak:
/* A macro to disable the copy constructor and assignment operator.
When building with C++11 and above, the methods are explicitly
deleted, causing a compile-time error if something tries to copy.
For C++03, this just declares the methods, causing a link-time
error if the methods end up called (assuming you don't
define them). For C++03, for best results, place the macro
under the private: access specifier, so that most attempts at
copy are caught at compile-time. */
Thanks,
Pedro Alves