setbuf() - I/O Function
How is "setbuf()" used in C++?
is an I/O function which is used to set the stream buffer, the function is set to NULL to turn off buffering. This function does not return any value.
void setbuf( FILE * stream, char * buffer );
FILE *str = fopen("setbufeg.txt", "wt");
fputs("A, B, C, D", str);
In the above example the buffered data is written to the file used by the stream only when the "fflush" function is called.