FWD: [bug #59270] [PATCH] node.h: avoid C++11 feature (non-const init in class)

[Ingo Schwarze]

Hi,

this is the second portability issue that killed the build for me.
Again, i'm looking for an OK to push the fix.

Since i have little experience with C++, please check that the fix
is correct and matches your intent.

I don't think a Changelog entry is needed here, either.  This mini-issue
never made it into a release and no user-visible change is intended.

Yours,
  Ingo


----- Forwarded message from Ingo Schwarze -----

URL:
  <https://savannah.gnu.org/bugs/?59270>

                 Summary: [PATCH] node.h: avoid C++11 feature (non-const init
in class)
                 Project: GNU troff
            Submitted by: schwarze
            Submitted on: Wed 14 Oct 2020 01:34:45 PM UTC
                Category: Core
                Severity: 3 - Normal
              Item Group: Build/Installation
                  Status: None
                 Privacy: Public
             Assigned to: schwarze
             Open/Closed: Open
         Discussion Lock: Any
         Planned Release: None

    _______________________________________________________

Details:

Compilation fails with GCC 4.2.1, which is the latest GNU compiler available
under GPLv2:

In file included from ../src/roff/troff/div.cpp:29:
../src/roff/troff/node.h:629: error: ISO C++ forbids initialization of member
'is_dying'
../src/roff/troff/node.h:629: error: making 'is_dying' static
../src/roff/troff/node.h:629: error: ISO C++ forbids in-class initialization
of non-const static member 'is_dying'
*** Error 1 in . (Makefile:6860 'src/roff/troff/div.o': @echo " CXX     "
src/roff/troff/div.o;depbase=`echo src/roff/troff/div.o | sed 's|...)
*** Error 2 in /co/groff/build (Makefile:5317 'all')

While requiring C++11 is likely to make sense for many newer projects,
i don't think there is any benefit in groff requiring it, at least
not as long as it is trivial to avoid.

Compatibility with C++03 was broken in this commit:
commit c788cf8c6bbe939fa11f7ec032e525a7e33f41b6
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
Date:   Tue Sep 29 07:02:25 2020 +1000

The attached patch fixes the build with gcc 4.2.1.

    _______________________________________________________


commit 138c2a21c8cfe7108473d4da2bdf3ac5fb9736f2
Author: Ingo Schwarze <schwarze@openbsd.org>
Date:   Wed Oct 14 15:19:04 2020 +0200

    node.h: do not rely on C++11 features, fixes build with gcc 4.2.1

diff --git a/src/roff/troff/node.cpp b/src/roff/troff/node.cpp
index 4a4e7e1b..72fff1ce 100644
--- a/src/roff/troff/node.cpp
+++ b/src/roff/troff/node.cpp
@@ -1613,6 +1613,7 @@ output_file *the_output = 0;
 
 output_file::output_file()
 {
+       is_dying = false;
 }
 
 output_file::~output_file()
diff --git a/src/roff/troff/node.h b/src/roff/troff/node.h
index e1c1960f..1fba4603 100644
--- a/src/roff/troff/node.h
+++ b/src/roff/troff/node.h
@@ -626,7 +626,7 @@ class output_file {
   char make_g_plus_plus_shut_up;
 public:
   output_file();
-  bool is_dying = false;
+  bool is_dying;
   virtual ~output_file();
   virtual void trailer(vunits);
   virtual void flush() = 0;