SQLite UDF-VBAコールバック

Question

ではもう過VBA（VB6)機能(AddressOf?) のSQLiteをUDF機能http://www.sqlite.org/c3ref/create_function.html).

どのようにコールバック関数の引数を取り扱うVBA?

の機能と呼ばれるように以下の署名...

void(xFunc)(sqlite3_context,int,sqlite3_value**)

Answer 1

残念ながら、を使用することはできませんVB6/VBA機能としてコールバックとして、VB6のみ発生 stdcall 機能により、 cdecl 機能SQLiteます。

する必要がありまC dllプロキシの通話後には再コンパイルSQLiteをサポートユーザーインターフェイスです。

後の再コンパイルを伴おdllをエクスポートする機能として stdcall, は、あらかじめ登録することができ機能は次のコード:

'Create Function
Public Declare Function sqlite3_create_function Lib "SQLiteVB.dll" (ByVal db As Long, ByVal zFunctionName As String, ByVal nArg As Long, ByVal eTextRep As Long, ByVal pApp As Long, ByVal xFunc As Long, ByVal xStep As Long, ByVal xFinal As Long) As Long

'Gets a value
Public Declare Function sqlite3_value_type Lib "SQLiteVB.dll" (ByVal arg As Long) As SQLiteDataTypes    'Gets the type
Public Declare Function sqlite3_value_text_bstr Lib "SQLiteVB.dll" (ByVal arg As Long) As String        'Gets as String
Public Declare Function sqlite3_value_int Lib "SQLiteVB.dll" (ByVal arg As Long) As Long                'Gets as Long

'Sets the Function Result
Public Declare Sub sqlite3_result_int Lib "SQLiteVB.dll" (ByVal context As Long, ByVal value As Long)
Public Declare Sub sqlite3_result_error_code Lib "SQLiteVB.dll" (ByVal context As Long, ByVal value As Long)

Public Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (dest As Any, source As Any, ByVal bytes As Long)

Public Property Get ArgValue(ByVal argv As Long, ByVal index As Long) As Long
    CopyMemory ArgValue, ByVal (argv + index * 4), 4
End Property

Public Sub FirstCharCallback(ByVal context As Long, ByVal argc As Long, ByVal argv As Long)
    Dim arg1 As String
    If argc >= 1 Then
        arg1 = sqlite3_value_text_bstr(ArgValue(argv, 0))
        sqlite3_result_int context, AscW(arg1)
    Else
        sqlite3_result_error_code context, 666
    End If
End Sub

Public Sub RegisterFirstChar(ByVal db As Long)
    sqlite3_create_function db, "FirstChar", 1, 0, 0, AddressOf FirstCharCallback, 0, 0
    'Example query: SELECT FirstChar(field) FROM Table
End Sub