extern const (Was: Re: [gcc-in-cxx]: patches from multi-target-4_4-branch)

[Ian Lance Taylor]

Joern Rennecke <amylaar@spamcop.net> writes:

> Quoting Ian Lance Taylor <iant@google.com>:
>> Joern Rennecke <amylaar@spamcop.net> writes:
>>> 	* config/sh/sh.c (sh_attribute_table): Use extern in forward
>>> 	declaration.
>>> Common issue with declaring/defining const variables in C++.
>>
>> I've been doing this as
>>
>> #ifdef __cplusplus
>> extern
>> #endif
>
> These #ifdefs sprinkled over the code are awkward.  Could we use a #define
> for this?  E.g. put in system.h
> #ifdef __cplusplus
> #define CONST_VAR_DECL extern const
> #else
> #define CONST_VAR_DECL const
> #endif

Yes, that is certainly the way to go if it is in fact not safe to use
"extern const int i = 1;" for all C compilers.  I hadn't planned to deal
with this issue yet, but since you bring it up, we should decide whether
that construct is safe, or whether we need the macro.

Ian