I have programmed a small reminder application which beeps every few seconds as specified by the user:

#include <windows.h>
#include <stdio.h>

int main()
{
    int interval;
    printf("How often shall I remind you?\n");
    printf("Every x seconds: ");
    scanf("%d", &interval);

    if (interval < 0 || interval > 300)
    {
        printf("Invalid interval. Try 0 < interval < 300.");
        return 1;
    }

    int numofbeeps = 3600/interval;
    printf("Good. I will beep every %d seconds (that makes %d times) over the next 60 minutes.\n", interval, numofbeeps);

    for(int ctr=0 ; ctr < numofbeeps ; ctr  )
    {
        Sleep(interval*1000);
        Beep( 1000, 750 ); 
    }
    return 0;
}

Is there a way to continuously scan for user input (even during sleep times) and, upon a certain input, take a certain action (e.g. restart the reminder loop by overwriting a variable and some goto-use)?

CodePudding user response：

A process can specify a console input buffer handle in one of the wait functions to determine when there is unread console input. When the input buffer is not empty, the state of a console input buffer handle is signaled.

DWORD wait = WaitForSingleObject(GetStdHandle(STD_INPUT_HANDLE), interval*1000);
if (wait == WAIT_OBJECT_0)
  // read input
else if (wait == WAIT_TIMEOUT)
  // Beep?
else
  // Handle error