Re: [USRP-users] UHD logging: Are errors not handled through std::clog the same way as infos are? Or: How to implement a custom logging facility when restricted to the UHD C API?

2019-03-04 Thread Marcus Müller via USRP-users 
Dear Janos
On Mon, 2019-03-04 at 18:22 +0100, Janos Buttgereit via USRP-users
wrote:
> Hi,
> 
> I’m using the UHD C API from within a C++ application. The reason for
> that is that UHD is optionally loaded as dynamic library at runtime
> through dlopen in case the user wants to use an ettus device and has
> the uhd library installed and therefore I’m limited to only use
> functions declared as extern C.

No, that's not true – C++ functions are just as exported. They might
not have the naming you expect, but it really doesn't make a difference
to the underlying system whether your exposed functions are C or C++.
That is, AS LONG as you used the same compiler to compile UHD and your
main C++ program (C++ ABI isn't as canonical as I'd like it to be).
I haven't worked with it in a while, but Boost.DLL [1] might be quite
exactly what you're looking for.

> 
> I need some custom logging facility for my application as it is GUI
> based, e.g. certain errors should end up in alert windows and not in
> console prints. However I haven’t found any possibility to implement
> such logging when restricted to the C API only. So first question:
> Did I overlook something? Any pointer on how to get custom logging
> working without using the C++ API would be greatly appreciated.

The C API was never meant to give you the full C++-specific flexibility
– I doubt this will be reasonably complex when going through the C API.


> 
> In the meantime I tried to go a different way. This document 
> https://files.ettus.com/manual/page_logging.html tells me, that UHD
> uses std::clog for everything using the console logging backend. As
> no other part of my application makes use of std::clog I simply
> redirected std::clog to a custom std::streambuf instance where I
> handle the log strings. This works quite well for the [INFO] log
> messages, however [ERROR] messages seem to bypass std::clog and are
> still printed to the console. Is this intended behaviour or a bug as
> the document tells that all console logging goes through std::clog?

I must admit: a good question.

Best regards,
Marcus


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[USRP-users] UHD logging: Are errors not handled through std::clog the same way as infos are? Or: How to implement a custom logging facility when restricted to the UHD C API?

2019-03-04 Thread Janos Buttgereit via USRP-users 
Hi,

I’m using the UHD C API from within a C++ application. The reason for that is 
that UHD is optionally loaded as dynamic library at runtime through dlopen in 
case the user wants to use an ettus device and has the uhd library installed 
and therefore I’m limited to only use functions declared as extern C.

I need some custom logging facility for my application as it is GUI based, e.g. 
certain errors should end up in alert windows and not in console prints. 
However I haven’t found any possibility to implement such logging when 
restricted to the C API only. So first question: Did I overlook something? Any 
pointer on how to get custom logging working without using the C++ API would be 
greatly appreciated.

In the meantime I tried to go a different way. This document 
https://files.ettus.com/manual/page_logging.html 
 tells me, that UHD uses 
std::clog for everything using the console logging backend. As no other part of 
my application makes use of std::clog I simply redirected std::clog to a custom 
std::streambuf instance where I handle the log strings. This works quite well 
for the [INFO] log messages, however [ERROR] messages seem to bypass std::clog 
and are still printed to the console. Is this intended behaviour or a bug as 
the document tells that all console logging goes through std::clog?

Best regards
Janos Buttgereit___
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