来源：Pbrt

static int TerminalWidth() {
#ifdef PBRT_IS_WINDOWS
    HANDLE h = GetStdHandle(STD_OUTPUT_HANDLE);
    if (h == INVALID_HANDLE_VALUE || !h) {
        fprintf(stderr, "GetStdHandle() call failed");
        return 80;
    }
    CONSOLE_SCREEN_BUFFER_INFO bufferInfo = {0};
    GetConsoleScreenBufferInfo(h, &bufferInfo);
    return bufferInfo.dwSize.X;
#else
    struct winsize w;
    if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &w) < 0) {
        // ENOTTY is fine and expected, e.g. if output is being piped to a file.
        if (errno != ENOTTY) {
            static bool warned = false;
            if (!warned) {
                warned = true;
                fprintf(stderr, "Error in ioctl() in TerminalWidth(): %d\\n",
                        errno);
            }
        }
        return 80;
    }
    return w.ws_col;
#endif  // PBRT_IS_WINDOWS
}

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