check how many variable arguments are passed?

Roger Stoltz

Have a look here[^].

"It's supposed to be hard, otherwise anybody could do it!" - selfquote
"High speed never compensates for wrong direction!" - unknown

hansipet

May be that I have missed something. but here I don't can find something about the number of arguments...

CPallini

The sample shows how you can implement functions with a variable number of arguments using C. :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.

hansipet

HOw this works I know. But I need a way to know the number of variable arguments. Because if no one are used, I want to optimize the function...it's a lot faster. Best regards Hansjörg

CPallini

if optimization is your concern, then avoid to use variable number of arguments (or use a mechanism such as the main one, i.e. an array of arguments and its length passed to your function). BTW, referring to the MSDN sample (link given by Roger Stoltz) [^], nothing prevents you to use the marker to indicate the total number of arguments: does this fit your needs? :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.

hansipet

The marker is not so a good was i think... The problem is that it is not possible to define 2 methods in a class (same name). One with variable length parameter and one without...This would be the best solution for me too... I want to make a logger class in this way... class Logger{ void Log(LPCSTR format,...); void Log(LPCSTR message); } something like that. It is easier for the user to have allways the same name...Do you know any solution for that? arrays are also not so good..it's not easy to use... if not I have to give the function another name.... :( Best regards hansjörg

CPallini

hansipet wrote:

Do you know any solution for that?

No. BTW, why don't you emulate the behaviour of cout instead of the one of printf? :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.

hansipet

This would be a great solution...but how I can do this?

CPallini

The tricky part is customizing the >> operator. Have a look, for instance, at this article http://www.codeproject.com/cpp/Encoder.asp[^]. :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.

hansipet

Thank you...I will check this..

Roger Stoltz

If you're using this for logging purposes, why don't use CString::FormatV()? Like this:

void <YourClassName>::Log( LPTSTR pText, ... )
{
CString LogText;
va_list args;
va_start( args, pText );
LogText.FormatV( pText, args );

// Do whatever you want with the LogText...

}

This would make the function call similar to printf().

"It's supposed to be hard, otherwise anybody could do it!" - selfquote
"High speed never compensates for wrong direction!" - unknown

hansipet

I think this is in the MFC library and I don't can use it...

Roger Stoltz

hansipet wrote:

I think this is in the MFC library and I don't can use it...

Ok, then use vsprintf(). See here[^]. It works the same as the CString alternative, but in this case you have to provide the output buffer.

"It's supposed to be hard, otherwise anybody could do it!" - selfquote
"High speed never compensates for wrong direction!" - unknown