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The parenthesis around the call were the source of my self-induced problem. Although it is not a proper tail call, it does what is needed. Thanks for the answer. Al > Date: Fri, 1 Feb 2008 15:41:25 +0000 > From: lua@corsix.org > To: lua@bazar2.conectiva.com.br > Subject: Re: tail calls across the C API > > Note the parenthesise around the call to dn.gas - these truncate the > return values to a single value. Also be aware that a tail call does > not occur when calling a C function; the calling function remains on > the stack as the C function executes. > > On 01/02/2008, Al Pfalzgraf <alpfalzgraf@hotmail.com> wrote: > > > > I have a library function that has a variable number of return values. It > > uses a Lua interface function to format its arguments and pass back the > > return values from the library function. The intent was to use the tail > > call behavior to move the library function's returned values back to the Lua > > script that calls the Lua interface function. > > > > -- Get Attribute Single interface function for dn.gas library function > > function gas( className, InstanceId, attrName, comment ) > > return(dn.gas( className, Node[className]["id"], > > InstanceId, > > attrName, Node[className][InstanceId][attrName]["id"], > > Node[className][InstanceId][attrName]["type"], > > comment ) > > ) > > end > > > > The difficulty I am having is in the return values. By stepping through > > the library function it is known that two values are put on the stack to be > > returned, and the library function returns the value 2. When the returned > > values from the interface function are displayed the first is correct but > > the second is a nil value. > > > > Should this work or is there a better technique to use? > > > > Thanks, > > Al > > > > ________________________________ > > Connect and share in new ways with Windows Live. Get it now! Climb to the top of the charts! Play the word scramble challenge with star power. Play now! |