C/stdio.h/setbuf

setbuf: specifies the buffer that stream will use

<source lang="cpp">

//Header file: #include <stdio.h> //Declaration: void setbuf(FILE *stream, char *buf);

1. include <stdio.h>

int main () {

 char buffer[BUFSIZ];
 FILE *fp1, *fp2;
 fp1=fopen ("test.txt","w");
 fp2=fopen ("test2.txt","a");
 setbuf ( fp1 , buffer );
 fputs ("This is sent to a buffered stream",fp1);
 fflush (fp1);
 setbuf ( fp2 , NULL );
 fputs ("This is sent to an unbuffered stream",fp2);
 //Set buf to null to turn off buffering.
 //The buffer must be BUFSIZ characters long.
 //BUFSIZ is defined in <stdio.h>.  

 fclose (fp1);
 fclose (fp2);
 return 0;

}

      </source>