Solved

Can you pass a va_list as arguments to fill a CString (variable argument list)?

Posted on 1997-05-29
1
1,095 Views
Last Modified: 2013-12-03
I have a class member that accepts a string with formatting capability, and therefore can have multiple arguments to fill the format sections. Can I simply take the string I get and the argument list and send it to CString and let it do the work of stuffing? How can I do this. I want to take the formatted string and send it to an open I/O stream. I'm using MSVC++ 4.2 under Win95 and WinNT 4.x. (Must I just add my own function like the protected CString::FormatV)?)

Here's my function member:
/////////////////////////////////////////////////////////////////////////////////////////////////
// this function member will extract the arguments into a va_list, set the new string, and
// append the string to the open report file
// it will display an error if a file has not been opened first with OpenReportFile
// this function will allow the passing of arguments as used in the printf and
// CString::Format functions (see Microsoft VC++ help for information on formatting codes)
//
// Input Variables:  lpszformatstr - string of text to be written to open file w/formatting info
//                   ... - formatting variable argument list
//
// Output Variable: function status return (TRUE- success, FALSE- error)
BOOL KEMETReportClass::WriteLineToReportFile(LPCTSTR lpszformatstr, ...)
{
      // assure a good valid string
      ASSERT(AfxIsValidString(lpszformatstr,FALSE));

      // check that a file is actually open
      if (!FileOpened || reportfilehandle == NULL)
            {
            AfxMessageBox("KEMETReportClass Warning!\nNo File Has Been Opened.\nCannot Write Line.",MB_OK | MB_ICONEXCLAMATION);
            return(FALSE);
            }

      // stuff the text string into a formatted CString
      CString ReportLineTextString;
      va_list arglist;
      va_start(arglist,lpszformatstr);
      ReportLineTextString.Format("%s",lpszformatstr,arglist);
      va_end(arglist);

      // now check for empty string
      // if not empty, spit it to the file, othewise, display a NULL string error message
      if (!ReportLineTextString.IsEmpty())
            fprintf(reportfilehandle,"%s",ReportLineTextString);
      else
            {
            AfxMessageBox("KEMETReportClass Warning!\nCannot Write A NULL Text Line.",MB_OK | MB_ICONEXCLAMATION);
            return(FALSE);
            }
      
AfxMessageBox(ReportLineTextString);
      return(TRUE);
}
0
Comment
Question by:maknight
1 Comment
 
LVL 6

Accepted Solution

by:
jpk041897 earned 10 total points
ID: 1397711
valists separate strings from eachoter using nulls, for instance:

"String 1"\0"String 2"\0"String 3"\0\0

Deafault constructors for CString would only read the first string in the va list.

You would either have to derive a class from CString and add your own constructor or add a method that woud parse the va list and implement the functionality you desire.
0

Featured Post

Salesforce Made Easy to Use

On-screen guidance at the moment of need enables you & your employees to focus on the core, you can now boost your adoption rates swiftly and simply with one easy tool.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article shows how to make a Windows 7 gadget that extends its U/I with a flyout panel -- a window that pops out next to the gadget.  The example gadget shows several additional techniques:  How to automatically resize a gadget or flyout panel t…
A theme is a collection of property settings that allow you to define the look of pages and controls, and then apply the look consistently across pages in an application. Themes can be made up of a set of elements: skins, style sheets, images, and o…
This is Part 3 in a 3-part series on Experts Exchange to discuss error handling in VBA code written for Excel. Part 1 of this series discussed basic error handling code using VBA. http://www.experts-exchange.com/videos/1478/Excel-Error-Handlin…

828 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question