Re: Structures with byte arrays using fromstring cause segfault

[Brian G <brian@xxxxxxxxxxxxxxxx>]

Well I think it is all me, fromstring is static, perhaps it only returns 
an array does not set an array.

I seem to have know that at some point in time.

Oh well, I guess I was wrong.

On 5/19/24 18:05, Jussi Lahtinen wrote:
> I think fromstring() is just incompatible with normal arrays.
>
> Jussi
>
> On Mon, May 20, 2024 at 4:02 AM Jussi Lahtinen 
> <jussi.lahtinen@xxxxxxxxx> wrote:
>
>     Here is your code corrected:
>
>     Public Struct demo
>          tag[100] As Byte
>     End Struct
>
>     Public dtag As Struct Demo
>     Public theString As String = "This is a test string tag"
>
>     Public Sub main()
>
>          dtag.tag.fromstring(theString)
>
>          Print "Tag="; dtag.tag.tostring()
>
>          For i As Integer = 0 To theString.len - 1
>             dtag.tag[i] = Asc(theString[i])
>          Next
>          dtag.tag[i + 1] = 0
>
>          Print "Tag="; dtag.tag.tostring()
>
>     End
>
>     However, the fromstring() function still does nothing.
>
>
>     Jussi
>
>
>     On Sun, May 19, 2024 at 11:36 PM Brian G <brian@xxxxxxxxxxxxxxxx>
>     wrote:
>
>         When Working with structures with byte arrays, the copy of a
>         string to
>         the byte array
>         using fromstring() appears to corrupt memory
>
>         But using the tostring() seems to work correctly.
>
>         I have included  a simple script to demonstrate the issue.
>         The first line does a fromstring() and initially appears to do
>         nothing.
>
>         But the last line that frees the allocated memory causes a
>         segfault
>         sometimes.
>
>         Removing the line doing the fromstring() makes everything ok
>         on the free.
>
>         Maybe I am using this in an incorrect way?
>
>         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>         #!/usr/bin/env gbs3
>
>         public struct demo
>              tag[100] as byte
>         end struct
>
>         public dtag as demo = alloc(400)
>         public theString as string = "This is a test string tag"
>
>         public sub main()
>              dtag.tag.fromstring(theString)
>
>              print "Tag=";dtag.tag.tostring() ' prints nothing and in
>         fact the
>         content is not changed.
>
>              for i as integer = 0 to theString.len-1
>                 dtag.tag[i] = asc(theString[i])
>              next
>              dtag.tag[i+1]=0
>
>              print "Tag=";dtag.tag.tostring()
>
>              free(varptr(dtag))
>         end
>
>         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
>         -- 
>         ~~~~ Brian
--
~~~~ Brian

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