How to check for valid filename

[Otto]

Is there a function to check if a filename is valid?

Thanks in advance
Otto

[mmercado]

Is there a function to check if a filename is valid?

Hi Otto:

Try this:

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If File( "YourFile" )
   ?"it exist"
else
   ?"not exist"
endif

Regards.

Manuel Mercado

[Otto]

Thank you Manuel. I meant not if the file exists but if the name is valid, i.e. that only supported characters ( *,. Etc.) are included.
Regards,
Otto

const
{ for short 8.3 file names }
ShortForbiddenChars : set of Char = [';', '=', '+', '<', '>', '|',
'"', '[', ']', '\', '/', ''''];
{ for long file names }
LongForbiddenChars : set of Char = ['<', '>', '|', '"', '\', '/', ':', '*', '?'];

[nageswaragunupudi]

function FileValid( <testname> ) --> .t. or .f.

This was a function in CA-Tools in the old DOS Clipper times. XHarbour implemented this with some extensions. Should be available in Harbour too.

[Otto]

Thank you.
Regards,
Otto

[Otto]

Hello NageswaraRao,

I tried with xHarbour but I get an unresoved external errror.
Could you please tell me which lib I have to link.
Thanks in advance
Otto

[nageswaragunupudi]

Please include ct.lib

This is the lib that contains all old CA-Tools functions. ( Many of them are not needed in the present systems and for windows )

There must be a lib with similar name in Harbour too.

[Armando]

Otto:

Perhaps this can help you

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// The example implements the function LongFileValid() which tests
// if a long file name is valid

   PROCEDURE Main

      ? FileValid( "MyApp.prg" )                   // result: .T.

      ? FileValid( "My New Application.prg" )      // result: .F.

      ? LongFileValid( "My New Application.prg" )  // result: .T.

   RETURN

   FUNCTION LongFileValid( cFileName, lExtension )

      IF Valtype( lExtension ) <> "L"
         lExtension := .F.
      ENDIF

   RETURN FileValid( cFileName, 255, 255, lExtension, .T. ) 

It's from xHarbour Doc

Best regards

[driessen]

Otto,

I use this function :

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FUNCTION CheckFileName(cName)

   LOCAL CharNo  := {",","=","+","<",">","|","[","]","\","/"}
   LOCAL cResult := .T.

   FOR i=1 TO LEN(cName)
       IF AT(CharNo[i],cName) <> 0
          cResult := .F.
          i := LEN(cName)
       ENDIF
   NEXT

   MsgInfo("Filename is " + IF(cResult,"","not ") + "valid")

RESULT(cResult)

Just add the characters which are not allowed to the array.

In case of shortname, you can add a test to check the length of the filename.

Good luck.

Michel

[xProgrammer]

Hi all

Just a note of warning about checking for the validity of file names based on testing for forbidden characters. Remember that xBase strings can contain any character. CHR(0) through CHR(31) are not allowed in DOS file names. Also certain names are reserved for devices: CON, PRN, AUX, NUL, COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8, COM9, LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, and LPT9. Microsoft warns against using these names even with extensions. These restrictions might not be relevant normally but you should be aware that many of the functions that check for the validity of a filename are not 100% robust because they don't check for CHR(0) through CHR(31) nor do they check for reserved device names.

You might like to check out http://msdn.microsoft.com/en-us/library/aa365247.aspx

Please note that Linux/Unix is much less restrictive. The only characters I know to be forbidden are / (obviously because it separates directory names and the filename) and NUL. No drive names are required so : can be used. In Linux a leading . denotes a hidden file.

[James Bott]

I think if you use the file save as common control, then filename checking is handled by Windows.

See FWH's cGetFile() function.

James

[nageswaragunupudi]

Syntax of FileValid function in xHarbour:

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FileValid( <cFileName>     , ;
          [<nMaxName>]     , ;  // default 8.  Assign 255 for long file names
          [<nMaxExtension>], ; // default 3.  Assging 255 for lfn
          [<lNoExtension>] , ; // better retain the default .f.
          [<lSpaces>]        )  // default .f. .  Assign .t. for long file names