Header File 

conio.h  

Category 

Console I/O Routines 

Prototype 

int kbhit(void); 

Description 

Checks for currently available keystrokes. 

kbhit checks to see if a keystroke is currently available. Any available keystrokes can be retrieved with getch or getche.

If a keystroke is available, kbhit returns a nonzero value. Otherwise, it returns 0. 

Example  

#include <conio.h>
int main(void)
{
 cprintf("Press any key to continue:");
    while (!kbhit()) /* do nothing */ ;
    cprintf("\r\nA key was pressed...\r\n");
    return 0;
}

Portability