Crash in MapWInGis when increasing TilesTHreadPoolSize

MapWinGIS
1

Hello,

when increasing the TilesThreadPoolSize Property of the GlobalSettings Object and using OpenStreetMap the whole App crashes whenn zooming, or moving the map without any errormessage.
Taking a look into Windows eventlog shows, that there is a problem with libeay32.dll. (needed for https communication). When using a custom provider with the http protocol the problem does not occur.

Sample Code:

Imports MapWinGIS
Public Class Form1
    Private gs As New GlobalSettings

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        gs.TilesThreadPoolSize = 12
       AxMap1.TileProvider = tkTileProvider.OpenStreetMap
       AxMap1.ZoomBehavior = tkZoomBehavior.zbUseTileLevels
       AxMap1.Projection = tkMapProjection.PROJECTION_GOOGLE_MERCATOR
       AxMap1.Redraw()
    End Sub
End Class

Beware of increasing TilesThreadPoolSize when using a tileprovider that relies on the https protocol.
Tested on VS 2019 and MapwinGis 5.3.0

Best Regards
Frank

1 Like
2

Hi Frank,

I believe this is the same issue as I reported here and which itself references another post. For my particular purposes I just replaced libcurl.dll with a more recent one and removed libeay.dll and ssleay.dll and so far so good.

Regards,

Rob

1 Like
3

Hi Rob,

I’ve tired your proposal concerning the libraries but it failed with runtime error.
Beside we discovered that the number in TileThreadPoolSize, that is tolerated, depends on the machine’s processor. E.g. on a core i3 with 2 cores / 4 threads the software crashes even with TileThreadPoolSize set to 4.
As a consequence, we now set TileThreadPoolSize to 1 when accessing tiles per https-protocol

Regard,
Frank