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#161977 - 2006-05-17 01:22 AM File Handle questions
Gargoyle Offline
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When you open a file is the filehandle a global or local definition.

I.E. you open a file in a function, can you then do a writeline in another function using the proper file handle?
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#161978 - 2006-05-17 01:45 AM Re: File Handle questions
Shawn Administrator Offline
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Posts: 8611
Without trying, I would say most definitely yes - file handles are internal to kixtart and dont have scope - they would be "global" by default.
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#161979 - 2006-05-17 06:10 AM Re: File Handle questions
NTDOC Administrator Offline
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Garg,

Not sure if you'v seen this or not as not everyone has read the entire manual and not too many have memorized it but using this method should prevent any file handle issue.

Code:
FreeFileHandle( )

Action: Returns the first available file handle.
  
Syntax: FreeFileHandle ( )
  
Parameters: None.
  
Returns: 0 No file handle available. 
> 0 Numeric file handle.
  
 
See Also: Open( ), Close( ), ReadLine( ), WriteLine( )
   
Example: $Handle = FreeFileHandle()
IF $Handle > 0
   IF Open($Handle, @LDRIVE + "\CONFIG\SETTINGS.INI") = 0
      ;………
   ENDIF
ENDIF

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#161980 - 2006-05-17 08:38 AM Re: File Handle questions
Gargoyle Offline
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Yes I use that method all of the time. My question was more to the fact of ...

Code:

Function OpenFile()
  Open (1,"c:\config.sys",5)
EndFunction

Function Write2File($Handle)
  Writeline(1, "This is a test")
EndFunction


Where a better way probably would be....
Code:

$FH = FreeFileHandle()

Function OpenFile($FH)
Open ($FH,"C:\Config.sys",5)
EndFunction

Function Write2File ($FH)
Writeline ($FH,"Nobody uses this file anymore")
EndFunction
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#161981 - 2006-05-17 09:32 AM Re: File Handle questions
NTDOC Administrator Offline
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don't forget to close the file properly too.
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#161982 - 2006-05-17 12:39 PM Re: File Handle questions
Richard H. Administrator Offline
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be careful when using FreeFileHandle() - don't get caught out by this schoolboy error:
Code:
$fhLogFile=FreeFileHandle()
$fhOutFile=FreeFileHandle()
 
; Open log file...
If Open($fhLogFile,"c:\temp\log.txt",5) "CANNOT OPEN LOG FILE"+@CRLF Exit @ERROR EndIf
 
; Open out file...
If Open($fhOutFile,"c:\temp\out.txt",5) "CANNOT OPEN OUT FILE"+@CRLF Exit @ERROR EndIf
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#161983 - 2006-05-17 02:24 PM Re: File Handle questions
Shawn Administrator Offline
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Richard, you should probably explain in greater detail why that doesn't work.
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#161984 - 2006-05-17 08:03 PM Re: File Handle questions
NTDOC Administrator Offline
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Quote:

be careful when using FreeFileHandle() - don't get caught out by this schoolboy error:
Code:
$fhLogFile=FreeFileHandle()
$fhOutFile=FreeFileHandle()
 
; Open log file...
If Open($fhLogFile,"c:\temp\log.txt",5) "CANNOT OPEN LOG FILE"+@CRLF Exit @ERROR EndIf
 
; Open out file...
If Open($fhOutFile,"c:\temp\out.txt",5) "CANNOT OPEN OUT FILE"+@CRLF Exit @ERROR EndIf




Though perhaps not as obvious to some it would not work as Richard wrote it.

BOTH files would have a FreeFile number of 1 which would then cause an error.
$fhLogFile=FreeFileHandle()
$fhOutFile=FreeFileHandle()

Since the call is one right after the other without actually opening any file, they
will both end up having the same value for their var.
 
I would probably close the files in each of the IF blocks, but as in this example it could be closed at the end if you like..

Dim $fhLogFile, $fhOutFile, $RC
; Open log file... 
$fhLogFile=FreeFileHandle()
'Value for FREE LOG is: ' + $fhLogFile ?
If Open($fhLogFile,"c:\temp\log.txt",5)=0
  $RC=WriteLine($fhLogFile,'Wrting to LOG file okay'+@CRLF+'Freehandle is: '+$fhLogFile)
Else
  "CANNOT OPEN LOG FILE"+@CRLF
  Exit @ERROR
EndIf
 
; Open out file... 
$fhOutFile=FreeFileHandle()
'Value for FREE OUT File is: ' + $fhOutFile ?
If Open($fhOutFile,"c:\temp\out.txt",5)=0
  $RC=WriteLine($fhOutFile,'Wrting to OUT file okay'+@CRLF+'Freehandle is: '+$fhOutFile)
Else
  "CANNOT OPEN OUT FILE"+@CRLF
  Exit @ERROR
EndIf
 
$RC=Close($fhLogFile)
$RC=Close($fhOutFile)


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#161985 - 2006-05-17 11:17 PM Re: File Handle questions
Gargoyle Offline
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Thanks Doc, now that you say without opening a file, it would return the same value, it makes alot of sense. I geuss I have been lucky in that I only opened 1 file.

Great example.
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#161986 - 2006-05-18 09:24 AM Re: File Handle questions
Richard H. Administrator Offline
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Posts: 4946
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To close this one off, my preferred method is to create a simple wrapper for the Open() function. This probably also answers your original question about the scope of file handles too

Code:
Dim $fhLogFile, $fhOutFile
 
; Open log file... 
$fhLogFile=udfOpenFile("C:\temp\log.txt",5)
If @ERROR "CANNOT OPEN LOG FILE"+@CRLF Exit @ERROR EndIf
; Open out file
$fhOutFile=udfOpenFile("C:\temp\Out.txt",5)
If @ERROR "CANNOT OPEN OUT FILE"+@CRLF Exit @ERROR EndIf
  
Function udfOpenFile($sPath,Optional $iMode)
	If ""=$iMode $iMode=2 EndIf
	$udfOpenFile=FreeFileHandle()
	If @ERROR $udfOpenFile=0 Exit @ERROR EndIf
	If Open($udfOpenFile,$sPath,$iMode) $udfOpenFile=0 Exit @ERROR EndIf
	Exit @ERROR
EndFunction
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