Crash in MapWInGis when increasing TilesTHreadPoolSize


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
    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

1 Like

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.



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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