Re: [PATCH 1/6] New function null_stream

[Luis Machado <lgustavo@codesourcery.com>]

On 01/18/2017 09:18 AM, Simon Marchi wrote:
> On 2017-01-18 10:01, Luis Machado wrote:
>> On 01/18/2017 08:57 AM, Simon Marchi wrote:
>>> On 2017-01-18 09:53, Luis Machado wrote:
>>>> We're setting stream to NULL at the top of the function and then
>>>> checking if it is NULL (it obviously is) right after that? Am i
>>>> missing something?
>>>
>>> The "static" :).
>>
>> Oh, that's what i was missing!
>>
>> Can't we have a clearer way of reusing this stream? It looks cryptic
>> this way (at least i think it looks cryptic).
>
> With Pedro's ui_file c++ification series, there is a null_file
> specialization of ui_file, and it's just a global object that you can
> reference.
>
> Search for "null_file null_stream" in
>
>   https://sourceware.org/ml/gdb-patches/2017-01/msg00312.html

That is perfectly fine. The cryptic bit i was referring to was 
declaring/initializing a static variable inside this particular function.

It ought to be possible to initialize the static variable somewhere else 
and only do the null check/allocation in the function? Compilers will 
often zero these out too, so initializing to NULL may not even be needed?

The fact that the initialization only happens once but the source line 
is there forever can cause some confusion.