How to Parse Config.fpw Programmatically (148689)
The information in this article applies to:
- Microsoft Visual FoxPro for Windows 3.0
- Microsoft Visual FoxPro for Windows 3.0b
This article was previously published under Q148689 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:
- Open or Create the Config.fpw file as applicable,
- Search through the Config.fpw file for the MVCOUNT= entry.
- If it finds an entry, it modifies it to read MVCOUNT=2000.
- If it doesn't find an entry, it creates one.
- 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
| Modification Type: | Major | Last Reviewed: | 9/30/2003 |
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| Keywords: | kbcode KB148689 |
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