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On Sep 10, 11:34*am, "Johannes Schaub (litb)" <schaub-johan...@web.de>
wrote:
> ksamdev wrote:
> > Hi,
>
> > Is is possible to make clog output messages into two output stream
> > simultaneously, say: cout and ostream?
>
> > Unfortunately, ostream::rdbuf(...) allows to set only one at a time.
>
> > I'd like to have messages that are sent to clog to be output on the
> > screen and logged in file at the same time.
>
> "ostream"? That's the class type of cout, not an object's stream. You can
> write a rdbuf that writes into two different buffers like
>
> struct mybuf : streambuf {
> * mybuf(streambuf *a, streambuf *b)
> * *:a(a),b(b)
> * { }
>
> protected:
> * int overflow(int c) {
> * * if(a->sputc(c) == EOF) return EOF;
> * * if(b->sputc(c) == EOF) return EOF;
> * * return c;
> * } *
> private:
> * streambuf *a, *b;
>
> };
>
> You can then connect like the following, remembering to later restore clog.
>
> * * filebuf fb;
> * * fb.open(...);
>
> * * mybuf m(cout.rdbuf(), &fb);
> * * streambuf *b = clog.rdbuf(&m);
> * * clog << "i go into cout and into the file!";
> * * clog.rdbuf(b);

Thanks for the advice.

In the original email I was talking about any ostream other than cout:
it might be ofstream, cerr, osstringstream, etc.

Does your code work with <iomanip> (manipulators) ?

On Sep 10, 5:45 pm, ksamdev <ksam...@gmail.com> wrote:
> On Sep 10, 11:34 am, "Johannes Schaub (litb)" <schaub-johan...@web.de>
> wrote:
> > ksamdev wrote:

> > > Is is possible to make clog output messages into two
> > > output stream simultaneously, say: cout and ostream?

> > > Unfortunately, ostream::rdbuf(...) allows to set only one at a time.

> > > I'd like to have messages that are sent to clog to be output on the
> > > screen and logged in file at the same time.

> > "ostream"? That's the class type of cout, not an object's stream. You can
> > write a rdbuf that writes into two different buffers like

> > struct mybuf : streambuf {
> > mybuf(streambuf *a, streambuf *b)
> > :a(a),b(b)
> > { }

> > protected:
> > int overflow(int c) {
> > if(a->sputc(c) == EOF) return EOF;
> > if(b->sputc(c) == EOF) return EOF;
> > return c;
> > }
> > private:
> > streambuf *a, *b;
> > };

> > You can then connect like the following, remembering to later restore clog.

> > filebuf fb;
> > fb.open(...);
>
> > mybuf m(cout.rdbuf(), &fb);
> > streambuf *b = clog.rdbuf(&m);
> > clog << "i go into cout and into the file!";
> > clog.rdbuf(b);

> Thanks for the advice.

> In the original email I was talking about any ostream other
> than cout: it might be ofstream, cerr, osstringstream, etc.

> Does your code work with <iomanip> (manipulators) ?

What do manipulators have to do with streambuf?

--
James Kanze

On Sep 10, 1:26*pm, James Kanze <james.ka...@gmail.com> wrote:
> On Sep 10, 5:45 pm, ksamdev <ksam...@gmail.com> wrote:
>
>
>
>
>
> > On Sep 10, 11:34 am, "Johannes Schaub (litb)" <schaub-johan...@web.de>
> > wrote:
> > > ksamdev wrote:
> > > > Is is possible to make clog output messages into two
> > > > output stream simultaneously, say: cout and ostream?
> > > > Unfortunately, ostream::rdbuf(...) allows to set only one at a time..
> > > > I'd like to have messages that are sent to clog to be output on the
> > > > screen and logged in file at the same time.
> > > "ostream"? That's the class type of cout, not an object's stream. You can
> > > write a rdbuf that writes into two different buffers like
> > > struct mybuf : streambuf {
> > > * mybuf(streambuf *a, streambuf *b)
> > > * *:a(a),b(b)
> > > * { }
> > > protected:
> > > * int overflow(int c) {
> > > * * if(a->sputc(c) == EOF) return EOF;
> > > * * if(b->sputc(c) == EOF) return EOF;
> > > * * return c;
> > > * }
> > > private:
> > > * streambuf *a, *b;
> > > };
> > > You can then connect like the following, remembering to later restore clog.
> > > * * filebuf fb;
> > > * * fb.open(...);
>
> > > * * mybuf m(cout.rdbuf(), &fb);
> > > * * streambuf *b = clog.rdbuf(&m);
> > > * * clog << "i go into cout and into the file!";
> > > * * clog.rdbuf(b);
> > Thanks for the advice.
> > In the original email I was talking about any ostream other
> > than cout: it might be ofstream, cerr, osstringstream, etc.
> > Does your code work with <iomanip> (manipulators) ?
>
> What do manipulators have to do with streambuf?
>
> --
> James Kanze

I don't know. That's why I am asking.
Never mind then. Let me try this approach first.