[boost] Re: additional boost libraries?

From: Sven Van Echelpoel (sven.van.echelpoel_at_[hidden])
Date: 2004-07-22 11:12:09

Vladimir Prus <ghost <at> cs.msu.su> writes:

> 
> Probably, you could start by explaining your vision of the library first. Of 
> three points you've given:
> 

The problems I would like to solve for myself are:

1) Often you need to write progams that need to work on different versions of 
a particular OS, with later versions having additional API calls that you 
could use. You end up writing stubs for those functions that at runtime check 
the availability of the API function, use it if it's available or do something 
different when it's not. It would be nice if it could be coded like so:

void MyAPIStub()
{
  static imported_function<void()>   apiFunc( "ApiFunc", "OSLib" );

  if ( !apiFunc )
  {
    // do something here
  }

  apiFunc();
}

Altough I acknowlege that the locking required in multi-threaded progams would 
clutter the syntax (more than) a little.

2) When creating plugin interfaces, having to go through extern "C" is a bit 
ugly to me. At the same time it ditches the C++ type safety. Being able to 
export a C++ plugin function and have the import library figure out the name 
mangling for me would improve the both the readability and the correctness of 
the program

> * a simple interface to load a library by name or path and query the address 
> of symbols by name
> * a boost::function-like type that can bind to a function at runtime and 
call 
> it
> * a scoped_ptr or smart_ptr-like type that can bind to exported PODs at 
> runtime
> 
> The two last seems very vague for me. For example, how the second is 
different 
> from:
> 
>    boost::function<void (void)> f 
>         = static_cast<void (*void)>dlsym(h, "whatever")
> 
> - Volodya
> 
> 

Yeah, yesterday morning I was already thinking more of something like this

boost::function<void()> f1 = import<void()>( "lib", "whatever" );
boost::function<void()> f2 = import<void()>( lib, "whatever" );
boost::function<void()> f3 = import<void()>( lib, "whatever", some_decorator
() );

As far as the cdecl decorator and the tool is concerned. I have always 
considered it very likely that I would fail and not achieve what I want, but 
that won't stop me from trying.

Svenne