INFO: rewind(stdin) Clears Keyboard Buffer

• The C Run-Time (CRT), included with:
  • Microsoft C for MS-DOS, versions 5.1, 6.0, 6.0a, 6.0ax
  • Microsoft C/C++ for MS-DOS, version 7.0
  • Microsoft Visual C++ for Windows, 16-bit edition, versions 1.0, 1.5, 1.51, 1.52
  • Microsoft Visual C++, 32-bit Editions, versions 1.0, 2.0, 2.1, 4.0, 5.0, 6.0

SUMMARY

To clear the keyboard buffer in Microsoft C use the function rewind() with the stream STDIN, which is associated with the keyboard by default. The function fflush() clears the buffers that C programs use for stream level I/O. It does not clear the device buffer.

MORE INFORMATION

The following is an example that shows what happens when the keyboard buffer is not cleared, and then how to clear it:

Sample Code

/* Compile options needed: none
*/ 

#include <stdio.h>

void main(void)
{
   int ch ;

   puts( "Input two or more chars. One is read now." );
   ch = getchar();
   putchar( ch );
   putchar( '\n' );

   puts( "The next char is taken from stdin." );
   ch = getchar( );
   putchar( ch );
   putchar( '\n' );

   rewind( stdin );
   puts( "Input two or more chars. One is read now." );
   ch = getchar();
   putchar( ch );
   putchar( '\n' );

   rewind( stdin );
   puts( "You must enter another char because of the rewind(stdin)" );
   ch = getchar( );
   putchar( ch );
   putchar( '\n' );
} 

Additional query words: 8.00 8.00c 9.00 9.10

Keywords : kbcode kbCRT kbVC kbVC100 kbVC150 kbVC151 kbVC152 kbVC200 kbVC210 kbVC400 kbVC500 kbVC600
Version : MS-DOS:5.1,6.0,6.00a,6.00ax,7.0; WINDOWS:1.0,1.5,1.51,1.52; WINDOWS NT:1.0,2.0,2.1,4.0,5.0
Platform : MS-DOS NT WINDOWS
Issue type : kbinfo