Extract small string of text from larger string

I’m working on a bit of code that I want to extract a small piece of text form a larger text file.

At the moment I can open and read the entire text file and also pin point a start and end marker of the text I want to extract.

What I’m having trouble doing is creating a variable text string which contains the text between the 2 markers.

What I have so far is

Function ExtractText()
Dim sSearchText1 As String
Dim sSearchText2 As String
Dim sFileName As String
Dim sFileText As String
Dim strText As String

Dim strStart As Integer
Dim strEnd As Integer

Const ForReading = 1

sSearchText1 = "--**Part1**" ' start point
sSearchText2 = "--**Part2**" 'end point

sFileName = "C:\Scripts\Script.sql"

'Create instance of FileSystemObject.
Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objfile = objFSO.OpenTextFile(sFileName, ForReading)

'read entire contents of file, save to strText variable
strText = objfile.ReadAll

strStart = InStr(strText, sSearchText1)
strEnd = InStr(strText, sSearchText2)

End Function

If it's not a calculation do not use a function but a sub.

Sub tst()
  open "C:\Scripts\Script.sql" for input as #1
    msgBox split(split(Input(LOF(1),#1),"--**Part2**" )(0),"--**Part1**")(1),,"This is the text you were looking for"
  close #1
End Sub

In a function

Sub exemplum()
  msgbox tst("C:\Scripts\Script.sql"),,"Alternative"
End Sub

Function tst(c01)
  open c01 for input as #1
    tst =split(split(Input(LOF(1),#1),"--**Part2**" )(0),"--**Part1**")(1),,"This is the text you were looking for"
  close #1
End Function

Mid$(strText, strStart, strEnd - strStart)

Note: it's very misleading to have integer variables whose names start with 'str'!

@snb,
I think you are missing a quote at the start of the msgbox title string.