c++ - How can I call a member function via a stream insertion operator? -

Using GCC 4.8 with C ++ 11 is enabled, I have a class like this:

  class outstream {public: outstream & amp; Operator & lt; & Lt; (Const char * s); Outstream & amp; Operator & lt; & Lt; (Int n); Outstream & amp; Operator & lt; & Lt; (Unsigned int n); // ... Outstream & amp; Vformat (const char * fmt, __VALIST args); Outstream & amp; Format (const char * fmt, ...); };  

When I use this class by calling operators directly, then it works as I expected:

  Outstream Out; Out.operator & lt; & Amp; Lt; (1). Format ("Formatted% 4X", 2). Assistant. & Lt; & Lt; ("3 \ n");  

Output:

  1 formatted 0002 3  

Now, I want to get the same output but < Code> & lt; & Lt; By using streaming notation, maybe this way:

  Outstream Out; Outside & lt; & Lt; 1 & lt; & Lt; Format ("Formatted% 04X", 2) & lt; & Lt; "3 \ n";  

Of course, this will not compile, because there was no such operator for my Outstream.format () method streaming.

There may be a solution where format () was a free function that gives a string, but it should first be used in all buffers of format () Need to write requires a std :: string or some other pile or buffer usage without any solutions - a solution that creates the same code when calling directly to the operators.

Any suggestions

Edit, 2014-10-20:

• To better understand my needs: I use the GCC cross toolchain I'm on bare metal embedded development.
• I need to apply the solution to some different embedded target systems (most Cortex-M0 / M3 / M4). Some of them are very limited resources (RAM and Flash) and one part of my target system should be run without using any heaps.
• For some reasons, I have Stl iostream . However, the edit has been made by editing the iostream tag; I keep it set due to the thematic match and can get a solution to my problem which can also be applied to STL iostream .

Use of C ++ 14 (contains):

  template & lt; Typename ... Ts & gt; Class formatters {cst. * Fmt_; Std :: Tuple & LT; T ... & gt; Args_; Template & lt; Std :: size_t ... is & gt; Zero Extensions (Outstream and OS, STD :: Index_sense is <... & gt;) & amp; Amp; {Os.format (fmt_, std :: get & lt; is> (std :: move (args _)) ...); } Public: Template & lt; Typename ... Args & gt; Formatter (const char * fmt, args & args): fmt_ {fmt}, args_ {std :: forward & lt; ARGS & gt; (Args) ...} {} Friend Outstream & amp; Operator & lt; & Lt; (Outstream and OS, Formatter & amp; F) {std :: move (f). Expand (OS, std :: index_sequence_for & lt; ts ... & gt; {}); Return os; }}; Template & lt; Typename ... Args & gt; Formatter & LT; Args & amp; & Amp; ... & gt; Format (const char * fmt, erg and amp ... ... args) {returns {FMT, STD :: Forward & LT; ARGS & gt; (RGS) ...}; }              The object must be removed. Actually this function:  
  zero test_foo () {Outstream Out; Outside & lt; & Lt; 1 & lt; & Lt; Format ("Formatted% 04X", 2) & lt; & Lt; "3 \ n"; }  
 
: 
 
 . LC0: .string "% 4X formatted". LC1: .String "3 \ n" test_foo (): pushq% rbx $ 1,% asi lesson $ 16,% rp leik 15 (% rsp),% rdi call outstream :: operator & lt; & Lt; MLL $ 2,% ADX MLL $ .cc,% seimpm% rx,% rbx mmpc% racks,% rdi xorl% eax,% eax call outstream :: format (thief cons *, ...) movq% rbx,% rdi Movl $. Lc1,% esi Call Outstream :: Operator & lt; & Lt; (Char const *) Addq $ 16,% rsp popq% rbx ret  
 
 So everything is properly underlined; There is no trace of  formatter  in the code generated.