c++ - Redirecting cout to the new buffer that created with winapi -

i'm trying print new screen buffer i've create winapi it's going old buffer , doesn't show on screen, possible, redirecting cout new screen buffer created using winapi?

#include <iostream> #include <windows.h>  int main() {     handle stdbuf, nbuf;     dword numberofchars;      stdbuf = getstdhandle(std_output_handle);     nbuf = createconsolescreenbuffer(generic_write, 0, null, console_textmode_buffer, null);      setconsoleactivescreenbuffer(nbuf);     setstdhandle(std_output_handle, nbuf);      // showing on screen     writeconsole(nbuf, "second buffer", 13, &numberofchars, null);      // going first buffer     std::cout << "second buffer cout" << std::endl;      sleep(3000);      setconsoleactivescreenbuffer(stdbuf);     closehandle(nbuf);      int = 0;     std::cin >> a;     return 0; } 

yes, it's possible. no, it's not entirely trivial.

the basic problem simple: there existing stream buffers talk named file, (probably) not existing 1 talk console. work, need 1 talks console. here's simple starting point:

class outbuf : public std::streambuf {     handle h; public:     outbuf(handle h) : h(h) {} protected:     virtual int_type overflow(int_type c) override {         if (c != eof) {             dword written;             writeconsole(h, &c, 1, &written, nullptr);         }         return c;     }      virtual std::streamsize xsputn(char_type const *s, std::streamsize count) override {         dword written;         writeconsole(h, s, count, &written, nullptr);         return written;     } }; 

[note: incomplete--it console output fine, if (for example) copy or assign it, bad things may happen--the usual rule of 0/3/5 applies.]

once have stream buffer writes output console, connecting cout pretty trivial:

console_stream_buffer buff(nbuf);  std::cout.rdbuf(buff);  std:cout << "bleh"; // should go console `nbuf`. 

here's quick demo using it:

int main() {      handle h = createconsolescreenbuffer(generic_write, 0, null, console_textmode_buffer, null);     handle original = getstdhandle(std_output_handle);      // create our stream buffer object     outbuf ob(h);      // write original buffer     std::cout << "first console";      // set cout go second buffer     std::cout.rdbuf(&ob);      // write     std::cout << "second console";      // display second buffer     setconsoleactivescreenbuffer(h);      // show second buffer few seconds:     sleep(5000);      // restore original buffer     setconsoleactivescreenbuffer(original); } 

you could, of course, write stream buffer allocates console screen buffer itself, if wanted to. left separate now, depending on how you're using things, may make more sense combine them (and include activate member calls setconsoleactivescreenbuffer well). none of relevant original question though, i'll leave now.