Holding scroll-bar gets command prompt to pause in Windows

Question

I have a program where I record data through an ADC system from National Instruments (NI).

The device buffers information for some time, and then the program collects the buffer data at some point. If the program collects data larger than the buffer, then the buffer would have to free without my program receiving the data, which will cause the NI library to throw an exception saying that requested data isn't available anymore, since it was lost.

Since my program is a command-prompt program, if the user clicks and holds the scrollbar, the program pauses, which could get this problem to happen.

How can I get over this problem without increasing the buffer size? Can I disable this holding thing in Windows?

Thanks.

Answer 1

Only the thread that is attempting to output to the console is blocked. Make this a separate thread, and your problem goes away.

Of course, you'll need to buffer up your output, and do something sensible if the buffer overflows.

For reference, here's the simple code I used to test this, you will note that the counter continues to increase even when the scroll bar is held down:

#include <Windows.h>
#include <stdio.h>

volatile int n = 0;

DWORD WINAPI my_thread(LPVOID parameter)
{
    for (;;)
    {
        n = n + 1;
        Sleep(800);
    }
}

int main(int argc, char ** argv)
{
    if (!CreateThread(NULL, 0, my_thread, NULL, 0, NULL))
    {
        printf("Error %u from CreateThread\n", GetLastError());
        return 0;
    }
    for (;;)
    {
        printf("Hello!  We're at %u\n", n);
        Sleep(1000);
    }
    return 0;
}