Support #4424
open(boost:: && std::) bind of Wt::WApplication* application_creator fails with too few arguments
0%
Description
This is the problem I asked a few weeks ago on stackoverflow in the Wt section, so for better formatting I recommend reading there:
http://stackoverflow.com/q/31968857/3537677
--- Summary of link content
I want to bind my additional parameters for my Wt::WApplication* MDDB_Service::application_creator(const Wt::WEnvironment& env, int foo); function like in the example. My solution compiles perfectly with gcc/mingw but with MSVC/Visual Studio 2013 Express, it fails with the error: "Error 94 error C2198: 'Wt::WApplication *(__cdecl *)(const Wt::WEnvironment &,int)' : too few arguments for call ...include\boost\function\function_template.h"
I used Wt::WRun(argc, argv,boost::bind(MDDB_Service::application_creator, _1, 5)); and also Wt::WRun(argc, argv,std::bind(MDDB_Service::application_creator, std::placeholders::_1, 5));. ¶
The audience at stackoverflow supposes that this bug may be related to the fact that the default constructor of Wt::WEnvironment is not public.
Wt version : 3.3.4.
Updated by Benoit Daccache over 8 years ago
- Tracker changed from Bug to Support
- Status changed from New to Feedback
Hey Markus,
If application_creator is not a static method your bind should take the instance of the class:
eg.
Wt::WRun(argc, argv,std::bind(&MDDB_Service::application_creator,mddb_instance_pointer, std::placeholders::_1, 5));
Otherwise your bind is maybe missing an '&' before the MDDB_SERVICE:
Wt::WRun(argc, argv,std::bind(&MDDB_Service::application_creator,mddb_instance_pointer, std::placeholders::_1, 5));
The instance to WEnvironment will be passed by WRun to the bound function/method, so the visibility of the constructor is not the problem here.
Exemple of working code:
@
WApplication *createApplication(const WEnvironment& env, int i)
{
return new Test(env);
}
int main(int argc, char **argv)
{
return WRun(argc, argv, std::bind(&createApplication, std::placeholders::_1, 1));
}
@
Benoit
Updated by Markus Klemm over 8 years ago
Benoit Daccache wrote:
If application_creator is not a static method your bind should take the instance of the class:
No MDDB_Service is just a namespace, it wasn't a member function /method. And the &operator didn't make a difference.
Anyway:
I was able to reproduce it with your code
@
Wt::WApplication *createApplication(const Wt::WEnvironment& env, int i) {
return new Wt::WApplication(env);
}
int main(int argc, char argv)
{
Wt::WRun(argc, argv,std::bind(&createApplication, std::placeholders::_1, 1));
}
@
Full file and boost snippet error refers to: https://gist.github.com/Superlokkus/fac974528a3831adf165
Error: Error 94 error C2198: 'Wt::WApplication *(__cdecl *)(const Wt::WEnvironment &,int)' : too few arguments for call c:\users\klm\downloads\wt-3.3.4-msvs2013-windows-x86-sdk\include\boost\function\function_template.hpp 95 1 MDDB_Web
BTW: I use your prebuilt binary (with the included boost library).
Updated by Wim Dumon over 8 years ago
Hello,
Your example compiles on my Windows installation on msvs 2013. Granted, I didn't try with our prebuild binaries, but my development setup your code works. It may have been a problem in boost that's solved in the meantime?
BR,
Wim.
Updated by Markus Klemm over 8 years ago
Wim Dumon wrote:
It may have been a problem in boost that's solved in the meantime?
I guess, I'm only using this boost version and msvs 2013 at all, because building Wt is a pain in **, because of the build system of the dependencies.
In the other hand I could be less a official problem of boost, but of msvs 2013, caused by it's limited C++11 support.
Could anyone help me out with a Wt build for MSVS 2015 x64 please, with the full pdf and raster support? I suppose for the sake of compatibility the built packages should be updated anyway.
Updated by Wim Dumon over 8 years ago
Next release will most likely have a msvc2015 build too. However I already noticed not all dependencies compile well with msvs 2015...
Wim.