Example from book, don't understand.

I am doing the 'building monster' example from the "Game Programming All in One" and there is something I dont quite understand from the code written. I have re-written the entire thing by hand and it works fine but there are still a few peices of code that I don't know why it works. For Example the author uses code that seemingly is not declared, (has no type and no declaration) it is just used. Here is a small part of the code....

Code:

//ConLib Class
enum ConColor
{
     ConRed = 1, 
     ConGreen = 2,
     ConBlue = 4
};

class ConLib
{
      HANDLE m_screen;
      HANDLE m_keyboard;
      
      WORD   m_TextColor;
      WORD   m_BackgroundColor;
      
      public:
             ConLib();
             ~ConLib();
             
             void SetBackgroundColor (WORD Color);
             void SetTextColor (WORD Color);
             void SetTitle (char * Title);
             void SetPosision (COORD Position);
             
             void Clear (void);
             void OutputString (char * String);
             
             void Read (char * Buffer, DWORD BufferSize);
             int GetKey (void);
};

I understand the ConLib() class above.

Code:

ConLib::ConLib()
{
 m_Screen = GetStdHandle (STD_OUTPUT_HANDLE);
 m_Keyboard = GetStdHandle (STD_INPUT_HANDLE);
 
 SetTextColor (ConRed | ConGreen | ConBlue);
 SetBackgroundColor (0);
}

ConLib::~ConLib()
{
}

void ConLib::SetBackgroundColor (WORD Color)
{
     m_BackgroundColor = 0;
     
     if (Color & ConRed)
     {
        m_BackgroundColor |= BACKGROUND_RED;
     }
     if (Color & ConGreen)
     {
        m_BackgroundColor |= BACKGROUND_GREEN;
     }
     if (Color & ConBlue)
     {
        m_BackgroundColor |= BACKGROUND_BLUE;
     }
     
     SetConsoleTextAttribute (m_Screen, m_TextColor | m_BackgroundColor);
}

The part in bold is what I don't understand. It is not defined anywhere else in the entire program, the author just uses it here and in many other places. It goes into it talking about how its defined...

Code:

BOOL SetConsoleTextAttribute (HANDLE hConsoleOutput, WORDwAttributes);

and then goes on describing the paramaters. What I don't understand is that the code, used in the class, does not contain the type BOOL but it works. I don't know if I am asking this the right way. I just don't understand cause it looks like a function call with no type and no declaration. Why does this work and not cause errors?

its a win32 api function, declared in windows.h