Re: WaitForSingleObject on Console not working???

From:
"Tom Widmer [VC++ MVP]" <tom_usenet@hotmail.com>
Newsgroups:
microsoft.public.vc.language
Date:
Thu, 13 Jul 2006 11:08:01 +0100
Message-ID:
<#2Yu6QmpGHA.1440@TK2MSFTNGP03.phx.gbl>
kimso.zhao@gmail.com wrote:

How can I know if there is input or not from keyboard in console
application? I want to flush buffer to screen every second.

In Unix, select( ) with stdin and timeout can work well( return timeout
every second ), but in Windows, stdin is NOTSOCK, hence select won't
work.

In Windows, WaitForSingleObject( stdinHandle, 1000 ) will return
"WAIT_OBJECT_0" when waiting for input.

How come the following always goes into "WAIT_OBJECT_0"?


Because there is some input on the handle at startup (probably a
FOCUS_EVENT_RECORD), and until you read that, wait calls will return
immediately.

What could I do? Is there any way to use select( ) in Windows with
stdin?

Thanks!


Try playing with this:
#include <windows.h>
#include <stdio.h>

int main()
{
    printf("->");
    static HANDLE stdinHandle;
    // Get the IO handles
    // getc(stdin);
    stdinHandle = GetStdHandle(STD_INPUT_HANDLE);

    while (1)
    {
        DWORD rc = WaitForSingleObject(stdinHandle, 1000);

        if( rc == WAIT_TIMEOUT )
        {
            printf("Timeout...");
        }
        else if( rc == WAIT_ABANDONED )
        {
            printf("WAIT_ABANDONED");
        }
        else if( rc == WAIT_OBJECT_0 )
        {
            printf("WAIT_OBJECT_0");
            INPUT_RECORD r[512];
            DWORD read;
            ReadConsoleInput(stdinHandle, r, 512, &read);
            printf("Read: %d", read);
        }
        else if( rc == WAIT_FAILED )
        {
            printf("Error:%d.", GetLastError());
        }
    }

    return 0;
}

Tom (again!)

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