vb 调用C写的动态库奇怪的问题！

[cmt123]

我用VB调用C写的动态库，发现奇快的问题，在调试时函数返回为-21，编译后返回函数0，大家帮帮我啊。
C函数：ret = JBC7K2_SetTime(g_devip,g_devport);
VB中声明：Public Declare Function JBC7K2_SetTime Lib "JBC7200.dll" (ByVal ip As String, ByVal port As Integer) As Integer

[worldy]

int WINAPI JBC7K2_SetTime(char *ip, int port)
的VB声明有问题：c 的int对应于VB为long

Public Declare Function JBC7K2_SetTime Lib "JBC7200.dll" (ByVal ip As String, ByVal port As Integer) As Integer

Public Declare Function JBC7K2_SetTime Lib "JBC7200.dll" (ByVal ip As String, ByVal port As long) As long

[贝隆]

[Quote=引用 2 楼 worldy 的回复:]
int WINAPI JBC7K2_SetTime(char *ip, int port)
的VB声明有问题：c 的int对应于VB为long

Public Declare Function JBC7K2_SetTime Lib "JBC7200.dll" (ByVal ip As String, ByVal port As Integer) As Integer

Public De……
[/Quote]
赞同，先按这个试一试

[cmt123]

不行，我试过了啊 Public Declare Function JBC7K2_SetTime Lib "JBC7200.dll" (ByVal ip As String, ByVal port As long) As long

[赵4老师]

调用时参数不要用String要用比如String*10并且以CHR(0)结尾

[of123]

Public Declare Function JBC7K2_SetTime Lib "JBC7200.dll" (ByVal ip As Byte, ByVal port As Long) As Long

Dim ret As Long, ip(255) As Byte

ret = JBC7K2_SetTime(ip(0), 1) 

[myhaikuotiankong]

[Quote=引用 6 楼 of123 的回复:]
Public Declare Function JBC7K2_SetTime Lib "JBC7200.dll" (ByVal ip As Byte, ByVal port As Long) As Long

Dim ret As Long, ip(255) As Byte

ret = JBC7K2_SetTime(ip(0), 1)
[/Quote]可以试试

[cmt123]

int WINAPI JBC7K2_SetTime(char *ip, int port)

[fooljake]

你确信2次运行调用的是同一版本的dll吗？若没有把握，可用 “开始\程序\附件\系统工具\系统信息/软件环境/加载的模块”查看。很可能不是同一个路径的dll,原因也就是其中C代码本来不同,运行结果不同.