UNC change directory

[Aldo Cavini]

I found CHDIR can be used to select an UNC path (this is an undocumented use for that statement). Hence to set the current directory to a path I can do one of the following:

1 - If the path conatins a drive letter ( like E: ) I use CHDRIVE to set the drive and CHDIR to set the path
2 - If the path is an UNC, I only use CHDIR

Is this correct? Or must I use some API call to set the curret drive-path to an UNC?

Another question. Is it a good practice to use CHDIR to see if a path exists?

Aldo

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[This message has been edited by Aldo Cavini (edited May 03, 2001).]

[Aldo Cavini]

A question more. Let the current directory is c:\temp. If I execute the statement "CHDIR aldo", and "aldo" does not exist (neither file nor subdirectory), I get an ERR 53 instead of ERR 76. Have I to check for both error codes? What about ERR 75?

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(added later). I tested it, and found I get ERR 53 when CHDIR to a directory does not exist, and I get ERR 75 if I try to CHDIR to a name that is a file. Hence it is clear about errors 53 and 75 (I hope it really is), but not about errors 53 and 76.

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[This message has been edited by Aldo Cavini (edited May 03, 2001).]

[Lance Edmonds]

CHDIR was intended to return an error 76. This is a confirmed problem in the current version of the compiler and will be corrected in the next update to the compiler.

You can use a UNC name with CHDIR but we cannot guaranteed it will work on all operating system and network combinations.

I hope this helps!


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Lance
PowerBASIC Support
mailto:sup[email protected][email protected]</A>

[Aldo Cavini]

thanks lance. the following code verifies or creates a directory regardless of the branch nesting. it is written to work both on unc and dos style paths - it is own responsibility if one uses it on uncs...

remarks:
1- only powerbasic statements - no apis
2- only full path admitted (drive + full path, from the root)
3- the program checks both err 53 and err 76 on chdirs
4- may be it won't work on uncs (see lance's post)
5- thanks to james moneypenny (see http://www.powerbasic.com/support/pb...ead.php?t=3686 who gave me some ideas.

' action   :   0 verify only
'            <>0 create directory
   
' on return:   0 directory exists or is correctly created (create)
'              0 directory exists                         (verify)
'             -1 directory does not exist                 (verify)
'             -2 invalid drive / unc root
'             -3 error occurred                           (create)
   
function createverifypath( byval action as long, drivepath as string ) as long
  
local oldp as string
local driv as string
local path as string
local i    as long
   
  errclear                                      ' reset previous errors
  oldp = curdir$                                ' save the current directory
   
  path = rtrim$( drivepath, "\" ) + "\"         ' add a \ at the end if needed
   
  if left$( path, 2 ) = "\" then               ' extract "drive" for unc
    driv = "\" + parse$( path, "\", 3 ) + "\" + parse$( path, "\", 4 )
    path = mid$( path, len( driv ) + 1 )
    chdir driv                                  ' chdir at root for that drive
    
  elseif mid$( path, 2, 2 ) = ":\" then         ' extract drive for dos
    driv = left$( path, 2 )
    path = mid$( path, 3 )
    chdrive driv                                ' change drive
    if err = 0 then
      chdir "\"                                 ' chdir at root
    end if
   
  else                                          ' not full path: return error
    function = -2
    exit function
  end if
   
  if err <> 0 then                              ' error in switching to drive/root
    function = -2
   
  elseif action = 0 then                        ' verify only
    chdir path
    if err <> 0 then
      function = -1
    end if
   
  else                                          ' branches loop
    for i = 2 to parsecount( path, "\" ) - 1
      chdir parse$( path, "\", i )
      if err = 53 or err = 76 then              ' branch does not exist
        errclear
        mkdir parse$( path, "\", i )            ' creates the branch
        if err = 0 then
          chdir parse$( path, "\", i )          ' switch to the branch
        end if
      end if
      if err <> 0 then                          ' error occurred
        function = -3
        exit for
      end if
    next i
  end if
   
  if mid$( oldp, 2, 1 ) = ":" then
    chdrive left$( oldp, 2 )                    ' restores the original drive
  end if
  chdir oldp                                    ' restores the original path
   
end function

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[this message has been edited by aldo cavini (edited may 04, 2001).]

[Scott Turchin]

Also note, and please correct me if I am wrong but if you are changing DRIVES I understand you can still do a CHDIR without having to CHDRIVE?
Used to in Dos I thot, but I always do a ChangeDrive anyway just to be safe....



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Scott

[Lance Edmonds]

CHDIR can change the default path on the default drive, and it can also change the default path on non-default drives.

It does not change the current drive though, unless you happen to (sucessfully) use a UNC name. Basically, if you need to change the default drive, use CHDRIVE.

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Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[Aldo Cavini]

Scott,

if you try to use CHDRIVE on a UNC, you get an ERR 75. CHDRIVE only tests for the first letter of the drive parameter. An UNC starts with "\\" - the first character is a back-slash, hence it is an invalid drive identifier. This is the reason I can't use CHDRIVE on UNCs.

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