如何使用VB调用uewasp.DLL中的水蒸气性质函数

ali88

Private Declare Sub PT2H Lib "uewasp.DLL" (ByVal P As Double, ByVal T As Double, ByRef H As Double, ByRef Range As Integer)

Dim hh As Double
Dim rr As Integer

Private Sub Form_Load()
PT2H 3.6, 439.2, hh, rr
MsgBox hh
End Sub

dll 调用约定错误

如果用pt2h97则找不到入口点

在powerbuilder 中也出错

[此贴子已经被uesoft于2007-1-13 15:33:23编辑过]

ligb

ali88说的对！今天修改好了，还做了一个VB6.0实例。

错误原因在于原来声明

Private Declare Sub PT2H Lib "uewasp.DLL" (ByVal P As Double, ByVal T As Double, ByRef H As Double, ByRef Range As Integer)

中最后一个参数Range应为4字节长整数Long类型，即正确声明应为

Private Declare Sub PT2H Lib "uewasp.DLL" (ByVal P As Double, ByVal T As Double, ByRef H As Double, ByRef Range As Long)

原来的VB函数声明中所有的区域Range声明参数(ByRef Range As Integer)都是错误的，现在已经全部更正为长整数(ByRef Range As Long)。

从这里下载最新VB源代码http://www.uesoft.com/forum.php?mod=viewthread&tid=2611&extra=page%3D1

注意要先调用SETSTD_WASP 设置好计算公式，如下：

Rem 设置计算公式 STDID=97,采用IAPWS-IF97公式；STDID=67,采用IFC-67公式；默认STDID=97。
Public Declare Sub SETSTD_WASP Lib "uewasp.dll" (ByVal STDID As Long)
Rem 获得计算公式 STDID=97,采用IAPWS-IF97公式；STDID=67,采用IFC-67公式；默认STDID=97。
Public Declare Sub GETSTD_WASP Lib "uewasp.dll" (ByRef STDID As Long)

SETSTD_WASP 97

[此贴子已经被uesoft于2008-3-4 9:19:13编辑过]