Am I stupid? (I know. Loaded Question)

[Ben Clark]

I have been using PBDLL and PBCC for what seems like forever.
I consider myself pretty good. I have written numerous
heavy duty programs that have been running for years.
With the help of these forums, I can't even begin to count
all the things you guys have helped me with and taught me.

I ran into something the other day and for some reason I am
drawing a total blank. (Blank Look On Face. Dha!!!!)
If I have declared 2 variables:
Dim stX as String
Dim szY as ASCIIZ * 100

If I want to CAST the stX variable to be a ASCIIZ all I need
to do is:
stX = "Something"
szY = stX
Now the string information is in the ASCIIZ variable.
However, what if I want to go the other way.
szY = "Something"
stX = szY
This should work and it does.
Now the real question.
When a function is expecting a parameter to be String but the
variable is a ASCIIZ, how can I CAST it on the fly to be
a String.
Function Hello(stX as String) as Long

' This will result in an error. Param type mismatch
Result = Hello(szY) << Parm should be of type String

I know I can first move the szY into stX but the program I
am working on would require alot of this.
Is there any way to just convert it.
Example: Result = Hello(Trim$(szY))
This will work, however, any leading or trailing spaces will be
trimmed off. NOT what I want.
I guess the short version of this whole thing is:
Is there a function for:
String = MakeStringFromASCCIZ(asciiz)

Thanks


------------------

[Don Dickinson]

Put parenthesis around the asciiz variable. E.G.

'
'  testasc.bas compile with pbdll6
'
#dim all
#compile exe

Sub ShowMsg(z as String)
   MsgBox z
End Sub

Function PBMain()
   
   Dim z as ASCIIZ * 100
   z = "This is a test"
   ShowMsg (z)
   
End Function

Best Regards,
Don

------------------
dickinson.basicguru.com

[Edwin Knoppert]

I.o.w. use it ByVal

I 'always' make use of strings in the parameters.
Now you can use asciiz and strings both.

Function Hello( ByVal s AS String ) As ...

Had to much trouble using asciiz's as parameter(!!)


------------------

[Don Dickinson]

I was remiss in that there are more options ...

using ByVal parameters

Sub ShowMsg(ByVal z as String)
   MsgBox z
End Sub

Function PBMain()
   
   Dim z as ASCIIZ * 100
   z = "This is a test"
   
   '- Nothing special is needed because the
   '  parameter is declared ByVal
   '
   ShowMsg z
   
End Function

use a ByRef parameter (default)

Sub ShowMsg(z as String)
   MsgBox z
End Sub

Function PBMain()
   
   Dim z as ASCIIZ * 100
   z = "This is a test"
   ShowMsg ByCopy z
   ' *OR*
   ShowMsg (z)
End Function

--Don

------------------
dickinson.basicguru.com

[Don Dickinson]

I have a related question about asciiz parameters. If there's a sub like this:

Sub ShowMsg(z as ASCIIZ)

and I pass it a string like this ...

Dim s as String
s = "This is a string"
ShowMsg ByCopy s

is the s guaranteed to have a trailing nul because it's passed by copy. It seems to work for me, but to be safe I usually do this ...
ByCopy s + $nul

Is that necessary?

Thanks
Don

------------------
dickinson.basicguru.com

[Ben Clark]

Thanks for the quick response guys.
Wow!


------------------

[Bern Ertl]

posted by don dickinson:
is the s guaranteed to have a trailing nul because it's passed by copy. it seems to work for me, but to be safe i usually do this ...
bycopy s + $nul

is that necessary?

don,

i asked basically the same question a while ago. the answer appears
to be that is not necessary as long as:

1) pb continues to use windows ole string engine, and
2) windows continues to add null bytes.

check out: http://www.powerbasic.com/support/pb...ad.php?t=18118



------------------
bernard ertl

[Don Dickinson]

hmmm, that thread seems to indicate that it's safe to do if you trust M$ not to change what they're doing. I think I'd agree with Tom's last message and add my own $nul to the end.
Thanks,
Don

------------------
dickinson.basicguru.com

[Tom Hanlin]

I do like to write paranoid code. However, further research suggests to me
that adding the $NUL is probably overkill. Yes, it's conceivable that it may
some day be needed, but it's really pretty safe to rely on the current
handling. Of course, that depends on your comfort level, and adding the $NUL
does emphasize the ASCIIZ nature of the string, which is nice for documentation
purpose.

The bottom line is, it works either way. Do whatever suits you best.

------------------
Tom Hanlin
PowerBASIC Staff

[Lance Edmonds]

Don, when you write BYCOPY S + $NUL, you are creating an expression, and this is going to be passed BYCOPY anyway, so you can omit the BYCOPY keyword and receive the identical result.

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

[Don Dickinson]

Hey Lance, thanks - good point. Never thought of that even though it was sitting under my nose.

Best Regards,
Don

------------------
dickinson.basicguru.com