一个奇怪的问题，有兴趣的来讨论一下哈

[我是丁学]

VB6.0(SP5) + Win2000 Advance Server
新建工程，只有一个模块，（有一个窗体，不过没用上），模块代码如下：
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Private Declare Function GetSystemDirectory Lib "kernel32" Alias "GetSystemDirectoryA" _
(ByVal lpBuffer As String, ByVal nSize As Long) As Long
Private Declare Function SearchPath Lib "kernel32" Alias "SearchPathA" _
(ByVal lpPath As String, ByVal lpFileName As String, ByVal lpExtension As String, _
ByVal nBufferLength As Long, ByVal lpBuffer As String, ByVal lpFilepart As String) As Long

Private Sub Main()
Dim Directory , Filename As String
Dim lpFilepart As String
Dim Dir_charnum , Dim File_charnum As Long

'Search Sqlsrv32.dll for check if ODBC driver for SQL Server exist
Directory = Space(255)
Filename = Space(255)
Dir_charnum = GetSystemDirectory(Directory, 255)
Directory = Left$(Directory, Dir_charnum)
File_charnum = SearchPath(Directory, "Sqlsrv32", ".dll", 255, Filename, lpFilepart)
If File_charnum = 0# Then
MsgBox "您还没有安装SQL Server的ODBC驱动程序，系统无法正常运行，请先安装SQL Server的ODBC驱动再运行本系统！", vbOKOnly, "未找到SQL Server的ODBC驱动"
End
End If
End Sub
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奇怪的是运行结果总是不正确，Dir_charnum可以得到正确的值，但是Directory却一直是一串空格，始终不曾有值，最后解决了，但奇怪的，改动的只是变量声明方式，只是把原来一行声明两个或多个变量的地方，换成每行声明一个，也就是这样：
……
Dim Directory As String
Dim Filename As String
Dim lpFilepart As String
Dim Dir_charnum As Long
Dim File_charnum As Long
……
这样运行就是正确的，为什么呢？什么道理？还是BUG？