Converting Strings

[The feature associated with this page, MCI, is a legacy feature. It has been superseded by MediaPlayer. MediaPlayer has been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer instead of MCI, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

When you use the mciSendString function, all values passed with the command and all return values are text strings, so your application needs conversion routines to translate from variables to strings or back again. The following example retrieves the source rectangle and converts the returned string into rectangle coordinates.

BOOL GetSourceRect(LPTSTR lpstrAlias, LPRECT lprc) 
{ 
    TCHAR achRetBuff[128]; 
    TCHAR achCommandBuff[128]; 

    int result;
    MCIERROR err;
 
    // Build the command string. 
    result = _stprintf_s(
        achCommandBuff, 
        TEXT("where %s source"), 
        lpstrAlias); 

    if (result == -1)
    {
        return FALSE;
    }
    
    // Clear the RECT.
    SetRectEmpty(lprc);
 
    // Send the MCI command. 
    err = mciSendString(
        achCommandBuff, 
        achRetBuff, 
        sizeof(achRetBuff), 
        NULL);

    if (err != 0)
    {
        return FALSE;
    }
        
    // The rectangle is returned as "x y dx dy". 
    // Translate the string into the RECT structure. 

    // Warning: This example omits error checking
    // for the _tcstok_s and _tstoi functions.
    TCHAR *p; 
    TCHAR *context;

    // Left.
    p = _tcstok_s(achRetBuff, TEXT(" "), &context);
    lprc->left = _tstoi(p);

    // Top.
    p = _tcstok_s(NULL, TEXT(" "), &context);
    lprc->top = _tstoi(p);

    // Right.
    p = _tcstok_s(NULL, TEXT(" "), &context);
    lprc->right = _tstoi(p);
    
    // Bottom.
    p = _tcstok_s(NULL, TEXT(" "), &context);
    lprc->bottom = _tstoi(p);

    return TRUE;
}