DOCUMENT:Q148689  24-AUG-1999  [foxpro]
TITLE   :How to Parse Config.fpw Programmatically
PRODUCT :Microsoft FoxPro
PROD/VER:3.00 3.00b
OPER/SYS:
KEYWORDS:kbcode

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The information in this article applies to:

 - Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b 
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SUMMARY
=======

This article shows by example how to parse through a text file programmatically.
This example uses Config.fpw. The code searches for a specific entry, and then
it modifies the entry if it is found or adds it if not found.

You might want to use this technique in distributed applications, for example, to
control the operating environment.

MORE INFORMATION
================

This code example checks to determine if the Visual FoxPro system variable
MVCOUNT is less than 2000. If follows this process:

1. Open or Create the Config.fpw file as applicable,

2. Search through the Config.fpw file for the MVCOUNT= entry.

   a. If it finds an entry, it modifies it to read MVCOUNT=2000.

   b. If it doesn't find an entry, it creates one.

3. Write the modified file contents back to disk, and close the file.

Code Sample
-----------

   * Parsefpw.prg
   * ------------
   * To make this backward compatible to FoxPro 2.x, replace the MESSAGEBOX()
   * functions with WAIT WINDOWs
   *
   cNewLine   = "MVCOUNT=2000"+CHR(13)      && This is the line to change/add
   nUpdateStat = 0                          && Use to determine which message
   cVFPConfigLoc = SYS(2019)
   nFileHand   = FOPEN(cVFPConfigLoc, 2)    && open with read/write privileges
   IF nFileHand == -1                       && Can't find Config.fpw
     nFileHand = FCREATE(cVFPConfigLoc, 0)  && Create an Config.fpw
     IF nFileHand == -1                     && Can't create Config.fpw
       = FCLOSE(nFileHand)
       nUpdateStat = 1                      && Not existing, Cannot Create
     ELSE
       = FWRITE(nFileHand, cNewLine)
       = FCLOSE(nFileHand)
       nUpdateStat = 2                      && Not existing, Did Create
     ENDIF
   ELSE
     filesize = FSEEK(nFileHand, 0, 2)
     = FSEEK(nFileHand, 0, 0)               && position file pointer to BOF
     contents = FREAD(nFileHand, filesize)
     spos = RAT("MVCOUNT", UPPER(contents)) && from right to find last
   MVCOUNT

     IF spos <> 0                           && Contains "MVCOUNT" entry
       * len = length (for example, len=20+1=21 for "MVCOUNT = 30 ")
       * len = AT(CHR(13)+CHR(10), SUBSTR(contents, spos)) - 1 && w/o CR & LF
       len = AT(CHR(13)+CHR(10), SUBSTR(contents, spos)) + 1 && with CR & LF
       IF LEN = 0
         LEN = LEN(SUBSTR(contents, spos))
       ENDIF
     ELSE                                   && "MVCOUNT" Not there, append it
       LEN = AT(CHR(26), contents)          && CHR(26) = Escape = EOF marker
       IF LEN <> 0
         contents = LEFT(contents, LEN - 1)
         LEN = 0
       ENDIF
       spos = RAT(CHR(13)+CHR(10), contents, ;
       IIF(RIGHT(contents, 2) <> CHR(13)+CHR(10), 1, 2))
       spos = spos + IIF(spos = 0, 1, 2)
     ENDIF
     contents = STUFF(contents, spos, LEN, cNewLine)
     = FSEEK(nFileHand, 0, 0)
     = FWRITE(nFileHand, contents)
     = FCHSIZE(nFileHand, LEN(contents))
     = FCLOSE(nFileHand)
     nUpdateStat = 3                           && Did exist, Modified
   ENDIF
   ?? CHR(7)
   cMsg1 = "A file named Config.fpw must exist in <YourApp>"+CHR(13);
          +"startup directory. This file must contain an
   MVCOUNT=2000"+CHR(13);
          +"statement in order for the <YourApp> application to
   operate"+CHR(13);
          +"correctly."+CHR(13)+CHR(13)
   DO CASE
   CASE nUpdateStat = 1 && Not existing, Cannot Create
     =MESSAGEBOX(cMsg1+;
       +"The computer system could not find this file nor could it"+CHR(13);
       +"create one. Until one exists, <YourApp> cannot be used.",0)
   CASE nUpdateStat = 2 && Not existing, Did Create
     =MESSAGEBOX(cMsg1+;
       +"The <YourApp> startup directory did not include this"+CHR(13);
       +"file so one was created for you. The new Config.fpw file"+CHR(13);
       +"contains all the required settings for the <YourApp>"+CHR(13);
       +"application to run."+CHR(13)+CHR(13);
       +"In order to activate this statement you need to RESTART the"+CHR(13);
       +"<YourApp> application.",0)
   CASE nUpdateStat = 3 && Did exist, Modified
     =MESSAGEBOX(cMsg1+;
       +"Your existing Config.fpw file has now been modified to
   contain"+CHR(13);
       +"an MVCOUNT=2000 statement. To activate this statement you
   need"+CHR(13);
       +"to RESTART the <YourApp> application.",0)
   ENDCASE


Additional query words: VFoxWin

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Keywords          : kbcode 
Technology        : kbVFPsearch kbAudDeveloper kbVFP300 kbVFP300b
Version           : 3.00 3.00b

=============================================================================

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