[RESOLVED] Runtime error - "Bad DLL calling convention" while using UrlEscape API.

I am trying to use the UrlEscape API but I am not sure what mistake I have made in the declaration. I am also not familiar with using pointers in Visual Basic 6.

Code:

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Private Declare Function UrlEscape Lib "Shlwapi" Alias "UrlEscapeA" (ByVal pszURL As Long, ByVal pszEscaped As Long, ByRef pcchEscaped As Long, ByVal dwFlags As Long)

Private Const URL_DONT_ESCAPE_EXTRA_INFO = &H2000000
Private Const URL_BROWSER_MODE = &H2000000
Private Const URL_ESCAPE_SPACES_ONLY = &H4000000
Private Const URL_ESCAPE_PERCENT = &H1000
Private Const URL_ESCAPE_SEGMENT_ONLY = &H2000
Private Const URL_ESCAPE_AS_UTF8 = &H40000
Private Const URL_ESCAPE_ASCII_URI_COMPONENT = &H80000

Private Sub Form_Load()
Dim strReturn As String
Dim szSize As Long
Dim strInput As String
strInput = "https://www.google.com/#q=stack+overflow"
szSize = Len(strInput)
Call UrlEscape(StrPtr(strInput), StrPtr(strReturn), szSize, URL_BROWSER_MODE)
MsgBox strReturn
End Sub

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Try the sample on the webpage of Randy Birch:
http://vbnet.mvps.org/index.html?cod.../urlescape.htm

It uses the following declaration:

Code:

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Private Declare Function UrlEscape Lib "shlwapi" Alias "UrlEscapeA" (ByVal pszURL As String, ByVal pszEscaped As String, pcchEscaped As Long, ByVal dwFlags As Long) As Long

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As you can see both the input and the output URLs should be passed as a string.
No StrPtr() needed

See if you have better luck with this:

Code:

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Option Explicit

Private Const E_POINTER As Long = &H80004003
Private Const S_OK As Long = 0
Private Const INTERNET_MAX_URL_LENGTH As Long = 2048

Private Const URL_DONT_ESCAPE_EXTRA_INFO = &H2000000
Private Const URL_BROWSER_MODE = &H2000000
Private Const URL_ESCAPE_SPACES_ONLY = &H4000000
Private Const URL_ESCAPE_PERCENT = &H1000
Private Const URL_ESCAPE_SEGMENT_ONLY = &H2000
Private Const URL_ESCAPE_AS_UTF8 = &H40000
Private Const URL_ESCAPE_ASCII_URI_COMPONENT = &H80000

Private Declare Function UrlEscape Lib "Shlwapi" Alias "UrlEscapeW" ( _
    ByVal pszURL As Long, _
    ByVal pszEscaped As Long, _
    ByRef cchEscaped As Long, _
    ByVal dwFlags As Long) As Long

Private Sub Form_Load()
    Dim strInput As String
    Dim cchEscaped As Long
    Dim strReturn As String
    Dim HRESULT As Long

    strInput = "https://www.google.com/#q=stack+overflow"
    cchEscaped = (Len(strInput) * 3) \ 2 'Space estimate, cannot be empty.
    strReturn = Space$(cchEscaped)
    cchEscaped = cchEscaped + 1 'Add terminating NUL.
    HRESULT = UrlEscape(StrPtr(strInput), _
                        StrPtr(strReturn), _
                        cchEscaped, _
                        URL_BROWSER_MODE)
    If HRESULT = E_POINTER Then
        strReturn = Space$(cchEscaped)
        cchEscaped = cchEscaped + 1 'Add terminating NUL.
        HRESULT = UrlEscape(StrPtr(strInput), _
                            StrPtr(strReturn), _
                            cchEscaped, _
                            URL_BROWSER_MODE)
    End If
    If HRESULT = S_OK Then
        strReturn = Left$(strReturn, cchEscaped)
        MsgBox strReturn
    Else
        MsgBox "UrlEscape error " & Hex$(HRESULT)
    End If
End Sub

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Don't use it for web scraping. Web scraping is piracy.

You probably want different flags set anyway.

@Arnoutdv @dilettante Thanks! Both the codes are working perfectly.