INFO: kbhit() Does Not Take Character Out of Buffer

• The C Run-time (CRT) included with: - Microsoft C for MS-DOS, versions 5.1, 6.0, 6.0a, 6.0ax - Microsoft C for OS/2, versions 5.1, 6.0, 6.0a - Microsoft C/C++ for MS-DOS, version 7.0 - Microsoft Visual C++ for Windows, versions 1.0, 1.5 - Microsoft Visual C++ 32-bit Edition, versions 1.0, 2.0, 4.0, 5.0

SUMMARY

When an application tests the value returned by the kbhit() function, the application must explicitly remove the character from the keyboard buffer after entering the keystroke. Otherwise, kbhit() continues to return TRUE.

The following code example demonstrates the situation:

Sample Code

   /*
    * Compiler options needed: None
    */

   #include <conio.h>

   void main(void)
   {
      while (!kbhit())
         ;          // Waits for keystroke
      while (kbhit())
         getch();   // Empties buffer

      while (!kbhit())
         ;          // Waits for keystroke
      while (!kbhit())
         ;          // Does not wait for keystroke
   }

Keywords          : CRTIss kbcode kbfasttip
Version           : MS-DOS:5.1,6.0,6.00a,6.00ax,7.0; OS/2:5.1,6.0,6.00a;  WINDOWS:1.0,1.5; WINDOWS NT:1.0,2.0,4.0,5.0
Platform          : MS-DOS NT OS/2 WINDOWS
Issue type        : kbinfo