Re: [Boost-users] return type of boost::iostreams::stream<T>::read()

Subject: Re: [Boost-users] return type of boost::iostreams::stream<T>::read()
From: Struebing, Axel, le-tex (axel.struebing_at_[hidden])
Date: 2008-10-15 16:56:41

Hallo Éric,

although it is not an exact fit it will be of value in evaluating my options.

kind regards
Axel Strübing

> > Reading the documentation about boost::iostreams library I could not
> > find the information which return type the boost::iostreams::stream's
> > class is giving me calling read().
> >
> >From the documentation, a boost::iostreams::stream derives from an
> > std::basic_[i|o]stream, depending on the model of its underlying Device.
> > In your example, the device is a Source, so I guess that the stream
> > derives from std::basic_istream, whose read(char*, streamsize) method
> > returns a basic_istream, not a streamsize.
>
> The library offers the "streamsize read(stream, char*, streamsize)"
> function template. Using it in your example yould give something like (not
> tested):
>
>   #include <boost/iostreams/stream.hpp>
>   #include <boost/iostreams/device/file.hpp>
>   #include <boost/iostreams/operations.hpp>
>
>   int main(void){
>     namespace bio = boost::iostreams;
>     bio::stream<bio::file_source> istr(std::string("in.pdf"));
>     char buffer[10];
>     std::streamsize i = bio::read(istr,buffer,10);
>     return 0;
>   }
>
>
> HTH,
>
> Éric Malenfant
> ---------------------------------------------
> Two wrongs don't make a right but three rights make a left.
> --