CODEWITHSUNDEEP
winapi
Itaypk
Itaypk

Reputation: 1133

Why wouldn't FlushConsoleInputBuffer work as expected?

I'm trying to read console input in a loop, using Win32 API. I'm using the following (simplified) code:

do {

    WriteConsoleW(hStdout, L"Enter text: ", wcslen(L"Enter text: "), NULL, NULL);

    if (!ReadConsoleW(hStdin, buf, 1, &nCharsRead, NULL)) {
        // ... Handle error...
    }

    if (!FlushConsoleInputBuffer(hStdin)) {
        // ... Handle error ...
    }

    // ... Handle input ...

} while (!bValid);

However, for any length of input, unless I'm quitting the loop - ReadConsoleW will keep reading one character at a time (including the line break), but even after the FlushConsoleInputBuffer call the rest of the input will not be discarded. For example, if I'll enter a single letter - I'll see "Enter text: " printed three times. For 2 letters input it would be 4 prints, and so on. According to the FlushConsoleInputBuffer documentation, the console input buffer should be cleaned:

Flushes the console input buffer. All input records currently in the input buffer are discarded

Is there a bug in this function, or am I doing it wrong?

Upvotes: 2

Views: 830

Answers (1)

HD1920
HD1920

Reputation: 11

The ReadConsoleW function adds the line break caused by the enter key as two additional characters.

Upvotes: 1

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