Re: [lmi] PATCH: Building lmi with gcc 10 and C++20

[Greg Chicares]

On 2020-05-10 22:12, Vadim Zeitlin wrote:
[...]
> - pdf_command_wx.cpp:2458:53: error: implicit capture of ‘this’ via ‘[=]’ is 
> deprecated in C++20 [-Werror=deprecated]
>  2458 |         auto const output_two_column_super_header = [=,&table_gen]
>       |                                                     ^
>   pdf_command_wx.cpp:2458:53: note: add explicit ‘this’ or ‘*this’ capture
> 
>   Here I've followed the compiler advice by capturing "this" (we don't want
>   to make a copy of this object by capturing "*this") and also getting rid
>   of the implicit capture mode and capturing everything we need explicitly.

Capturing everything we need explicitly does have a certain charm,
albeit with a countervailing increase in verbosity:

-        auto const output_two_column_super_header = [=,&table_gen]
+        auto const output_two_column_super_header = 
[this,pos_y,output_mode,z,&table_gen]

so, when I began reading
  http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0806r2.html
I wondered why you didn't choose the elegant "[=, this]" alternative
(and why I hadn't encountered that syntax before). Then I read the last
sentence of the paper:

| The replacement [=, this] for the deprecated [=] is ill-formed in C++17
| and only available in C++20 as of P0409R2.

and was enlightened. It's probably not worth writing a preprocessor
conditional here.

Aside from that, I had no comments or questions concerning this
patchset. Thanks for doing all this work.