Re: coding style

"Jim Johnson" <aopiyy001@yahoo.com> ha scritto nel messaggio
news:lgldv39oat9jm42ur9m2n974l4h6gr3cfn@4ax.com...


The above is C++ code, because it uses 'catch' to catch exception
(_com_error &), and I believe it is not possible in pure C.

The CATCHERROR seems a preprocessor macro defined to avoid repeating
boiler-plate code.

Frankly speaking, if this macro is used wisely and not abused, I would not
define that bad code.
*Sometimes* preprocessor macros can come in handy.

e.g. I read some DirectShow SDK and COM code that uses HRCALL macro. It is
also available on MSDN.

<code>

// Macro that calls a COM method returning HRESULT value:
#define HRCALL(a, errmsg) \
do { \
    hr = (a); \
    if (FAILED(hr)) { \
        dprintf( "%s:%d HRCALL Failed: %s\n 0x%.8x = %s\n", \
                __FILE__, __LINE__, errmsg, hr, #a ); \
        goto clean; \
    } \
} while (0)

</code>

<code>

// Helper function that put output in stdout and debug window
// in Visual Studio:
void dprintf( char * format, ...)
{
    static char buf[1024];
    va_list args;
    va_start( args, format );
    vsprintf_s( buf, format, args );
    va_end( args);
    OutputDebugStringA( buf);
    printf("%s", buf);
}

// Helper function to create a DOM instance:
IXMLDOMDocument * DomFromCOM()
{
   HRESULT hr;
   IXMLDOMDocument *pxmldoc = NULL;

   HRCALL( CoCreateInstance(__uuidof(MSXML2::DOMDocument30),
                  NULL,
                  CLSCTX_INPROC_SERVER,
                  __uuidof(IXMLDOMDocument),
                  (void**)&pxmldoc),
                  "Create a new DOMDocument");

    HRCALL( pxmldoc->put_async(VARIANT_FALSE),
            "should never fail");
    HRCALL( pxmldoc->put_validateOnParse(VARIANT_FALSE),
            "should never fail");
    HRCALL( pxmldoc->put_resolveExternals(VARIANT_FALSE),
            "should never fail");

    return pxmldoc;
clean:
    if (pxmldoc)
    {
        pxmldoc->Release();
    }
    return NULL;
}
</code>

My 2 cents.

Giovanni