In C++ you have to export your functions with "C linkage", that is, you need
to wrap your functions or prototypes in a C linkage block.
extern "C"
{
__declspec(dllexport) long gettime();
...
}
long gettime()
{
...
}
Note also that your function declaration in C# has the wrong return type, a
long in C/C++ is 32 bit a long in C# is 64 bit.
[C#]
public static extern int gettime();
Willy.
"Tim Greenwood" <tim_greenwood A-T yahoo D-O-T com> wrote in message
news:uqTGmQF$FHA.2036@TK2MSFTNGP14.phx.gbl...[color=blue]
> this should be so simple....here is the code in my simple "C" dll
>
> #define DllExport __declspec(dllexport)
>
> #include <time.h>
>
> //DllExport
>
> long gettime(void);
>
> long gettime()
>
> {
>
> time_t tt = time(NULL);
>
> return (long)tt;
>
> }
>
> --------------------------------------------------------------------------
> here is the import in my C# app
>
> [DllImport("ctime.dll", CallingConvention=CallingConvention.Cdecl)]
>
> public static extern long gettime();
>
>
>
> -------------------------------------------
>
> I've tried several different CallingConventions and nothing same thing
> "Unable to find entry point named gettime in dll ctime.dll
>
>
>
>
>
>
>
>
> "Nicholas Paldino [.NET/C# MVP]" <mvp@spam.guard.caspershouse.com> wrote
> in message news:uzUlXzE$FHA.4088@TK2MSFTNGP09.phx.gbl...[color=green]
>> Tim,
>>
>> You should have received an error when you added it to your project.
>> If you have a function that is exported by a DLL, you need to call it
>> through the P/Invoke layer. If the dll is somewhere in the path where
>> LoadLibrary will find it, you can do this:
>>
>> [DllImport("<dll name here>.dll")]
>> static extern int myfunc();
>>
>> And then call the dll function in managed code.
>>
>> Hope this helps.
>>
>>
>> --
>> - Nicholas Paldino [.NET/C# MVP]
>> -
mvp@spam.guard.caspershouse.com
>>
>> "Tim Greenwood" <tim_greenwood A-T yahoo D-O-T com> wrote in message
>> news:%23faLcxE$FHA.3872@TK2MSFTNGP12.phx.gbl...[color=darkred]
>>>I am at my wits end here. I have a simple project with one global
>>>function returning a long value.
>>>
>>> __declspec(dllexport) long myfunc()
>>> {
>>> }
>>>
>>> I've built the dll, added it as a reference to my C# project. Now how
>>> in the world do I reference "myfunc" ????
>>> It totally eludes me.
>>>
>>> Many thanks for any help here.
>>>[/color]
>>
>>[/color]
>
>[/color]
