Re: [Discuss-gnuradio] GNURadio/Module builds and std=C++11

[Michael Dickens]

Looking through the gr-osmosdr source code, there is no c++ standard set
so CMake will default to something like c++98; not c++11 or later.

Looking through the libfreesrp code, it requires C++11 for building.
It's public API also requires C++11, so to get gr-osmosdr support for
freesrp you have to tell CMake to set the standard to C++11 when
building at least the freesrp portions of gr-osmosdr; possibly the whole
shebang since it's generally not wise mixing c++ runtime libraries.

Given the above, I'd guess you're not alone or unique in this specific
build, since this is the way the code is currently written. I haven't
tried any of the above on Mac OS X / macOS, as libfreesrp doesn't play
nicely with this OS yet & will take too much work for me to get going
given my limited availability.

Hope this helps! - MLD

On Tue, Jun 20, 2017, at 12:25 PM, Ghost Op wrote:
> I've run into this on every Ubuntu 16.04 box I've installed gnuradio
> and OOT modules on and Google doesn't seem to have a nice clean answer
> (the search answer is always add a compile flag) so I figured I'd ask
> the group.
> 
> When I build modules (gr-osmosdr in particular with libfreesrp support
> I run into this) on a fresh Ubuntu 16.04.2 LTS install, I run into a
> warning like this: "warning: non-static data member initializers only
> available with -std=c++11 or -std=gnu++11".  Depending on the code it
> may produce errors on some lines preventing compilation.
> 
> I know what causes it, the compiler is defaulting to something earlier
> than the  c++11 standard (like C++99) with the Ubuntu repo gcc version
> (5.4) installed, so some of the syntax in the code is causing the
> warning.  I can modify the CMake and add this to it "set
> (CMAKE_CXX_STANDARD 11)" and it builds after that, but my guess is
> that this builds on everyone else's Ubuntu without these modifications
> or the setting would be standard in the CMake files.  What I'd really
> like to do is tell the compiler to default to -std=C++11 even if it's
> not explicitly provided as a compile flag, but again if everyone were
> running into it I think it would have been fixed another way.
> 
> If I do the same build on a standard debian build with gcc 6.3 it
> builds clean so it's definitely a default standard issue for compilers
> on Ubuntu 16.04.
> 
> Does anyone have any insight/suggestions?