ostream_iterator

[Aman]

Hi,
please consider the following prog (SunOS 5.8,g++ compiler)
when I ran it through the debugger , I found that the program doesn't
output till either the "\n" or the exit .
(debugger ..Single stepping until exit from function _start ...)
what does reaching exit or \n have to do with cout or ostream_iterator
?


#include <iostream>
#include <string>
#include <iterator>
using namespace std ;

int main()
{
ostream_iterator<string> out(cout , " ") ;
*out ="hello" ;
out++ ;
*out = "world" ;
out++ ;
*out = "\n" ;
out++ ;
*out = "again" ;

}

regards,

 

[Mike Wahler]

Hi,
please consider the following prog (SunOS 5.8,g++ compiler)
when I ran it through the debugger , I found that the program doesn't
output till either the "\n" or the exit .
(debugger ..Single stepping until exit from function _start ...)
what does reaching exit or \n have to do with cout or ostream_iterator
?


#include <iostream>
#include <string>
#include <iterator>
using namespace std ;

int main()
{
ostream_iterator<string> out(cout , " ") ;
*out ="hello" ;
out++ ;
*out = "world" ;
out++ ;
*out = "\n" ;
out++ ;
*out = "again" ;

}

Output is not guaranteed to be delivered to the
device attached to a stream until a newline is
inserted into the stream, or the stream is explicitly
flushed, or the stream object is destroyed, or if
it is a file stream, the file is closed.

This is by design.

A 'special case' exists with regard to 'cin' and 'cout':
An insertion to 'cout' will first cause an automatic 'flush'
of 'cin' if any data remain in its stream buffer (see 'tie()')

HTH,
-Mike

 

[Aman]

Thanks , makes sense.
Is there anyplace where this behaviour is documented ?
url / book reference would be good.

regards,
Aman

 

[Mike Wahler]

Thanks , makes sense.
Is there anyplace where this behaviour is documented ?
http://tinyurl.com/31yw

url / book reference would be good.

http://www.langer.camelot.de/iostreams.htm
http://www.josuttis.com/libbook/

-Mike

 

[Aman Angrish]

Thanks a lot !!.

regards,
Aman.