setbuf

The virtual function setbuf is called by user code to offer an array for use as a holding area. It can also be used to turn off buffering.

   streambuf* fctbuf::setbuf(char* b, int len)
   {
   	if ( base() ) return 0 ;
   	
   	if ( b!=0 && len > sizeof(small) ) {
   		// set up holding area
   		setb(b,b+len) ;
   		}
   	else {
   		// Use a one character array to achieve
   		// "unbuffered" actions.
   		setb(small,small+sizeof(small)) ;
   		}
   	setp(0,0) ; 		// put area
   	setg(0,0,0) ;		// get area
   	return this ;
   	}

• base() points to the first character of the holding area. If a holding area has already been set up (base non-zero) a new one cannot be established and setbuf() returns a null pointer as an error indication.

• If an array is supplied and is sufficiently large, setb() is called to set up the pointers to the holding area. Its first argument becomes base, the first char of the holding area, and its second becomes ebuf, the char after the last. Otherwise the fctbuf will become unbuffered. This is noted by setting up a one character holding area.

• Finally the pointers related to the put area are set to 0 by setp() and the pointers related to the get area are set to 0 by setg().