How to Parse Config.fpw Programmatically

MORE INFORMATION

1. Open or Create the Config.fpw file as applicable,
2. Search through the Config.fpw file for the MVCOUNT= entry.
   1. If it finds an entry, it modifies it to read MVCOUNT=2000.
   2. 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