File Exists command???

[Gary Stout]

Is there a command in PB/DLL6 that will allow me to
check for the presence of an EXE file and if so, return
a value (1) that can be used if the file was found and a
(0) for instance if the file wasn't found?
I looked at DIR$, but that did'nt seem like what I needed.

Thanks,
Gary Stout

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[Edwin Knoppert]

ErrClear
a = GetAttr( sFileName )
If Err = 0 And IsFalse( a And %FILE_ATTRIBUTE_DIRECTORY ) Then
'File found...
End If

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[Steve Hutchesson]

Gary,

This is an old one of Dave Navarro's that has been doing the job for years.

FUNCTION Exist&(fname$)
  FUNCTION = Len( Dir$(fname$, 17) ) > 0
END FUNCTION

Regards,

[email protected]


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[Gary Stout]

Thanks guys,
I will give them both a try. Going to use this to enable or disable
menu items in EZGUI. If the EXE being search for is not found, then
then the menu item will be greyed out and disabled, otherwise,
it will be normal and able to be selected.

Thanks again,
Gary Stout

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[This message has been edited by Gary Stout (edited May 29, 2001).]

[Wayne Diamond]

Steve, which number in Dir$(path,number) will display all files? Ive been using Dir$(file,39) for the last year for some reason that I cant remember
The decimal values of each attribute:
readonly 1
hidden 2
system 4
directory 16
archive 32
normal 128

so Im assuming i put 39 together from 32+4+2+1 , which seems to be working fine to detect all files, regardless of their attributes
I prefer using a number such as 39 rather than %FILE_ATTRIBUTE_READONLY + %FILE_ATTRIBUTE etc etc
Which number do you use for files (regardless of the files attributes), and which for dirs?

Best regards,
Wayne


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[Tom Hanlin]

Wayne, only Hidden (2), System (4), and Directory (16) are search attributes.
So, to match all files, you just need 2+4+16 = 22.

The "normal" attribute is an oddball addition by Microsoft late in the game.
"Normal" used to be simply a file with no other attributes set. It is not
clear why a specific number is needed for "normal" or whether you can expect
to see it in combination with other bits, or exactly why Microsoft chose 128
when they must have known that Novell has always used this to mean "protected".


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Tom Hanlin
PowerBASIC Staff

[Paul Noble]

On the same subject, I wonder what is the best way to perform this
test on a network file, allowing for graceful recovery in the case
where say the connection may not currently exist.

Is it simply a case of trapping the error, or I wonder if timeouts
are involved ?

Could someone explain the pros & cons please ?

Thanks -

[This message has been edited by Paul Noble (edited May 30, 2001).]

[Scott Turchin]

You could test the errors such as the way this function (I've used this one for 3 years now)...
Test hDir for return error...
If the file exists but the pathing/mapping is wrong because of a network error you should get something like 'Network path not found'.

Function Exist(ByVal filespec As String) Export As Long
  Local hDir     As Long
  Local FindData As WIN32_FIND_DATA

  FindData.dwFileAttributes = %FILE_ATTRIBUTE_DIRECTORY
  hDir = FindFirstFile(ByVal StrPtr(filespec), FindData)
  Function = hDir
  If hDir = %INVALID_HANDLE_VALUE Then
    Exit Function     'file not found
  End If
  FindClose hDir
End Function

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Scott

[Paul Noble]

Thanks Scott, I just tested that and my own method (same as the
one originally posted), and both work fine in that situation.

The reason for asking was that a few years ago, I had a problem
in VB5 where it waited for ages before deciding it couldn't see
say "\\server\data\file.dat". I don't remember the outcome
now, but it certainly appears that it's not an issue from PB

[Scott Turchin]

ah...Well I see that when I open explorer, it goes out and makes sure the credentials are still good etc, makes sure the folder/share are still there...

And this function will ptu a lag on it too the first time you use the file/share if you have not logged in for a while...

I'm not sure what causes that exactly, perhaps just refreshing credentials


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Scott

[Lance Edmonds]

Sure. Network settings such as "Quick logon" and "Logon and restore connections" can definitely affect the speed of the first access to a network (mapped) drive.

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