DllImportAttribute CallingConvention

[Mr.Tickle]

I am calling an unmanaged DLL like follows in a Class wrapper.

namespace blah
{
[DllImport("DLLName.DLL", EntryPoint="BlahEntryPoint",
CallingConvention=CallingConvention.ThisCall]
public static extern void blahFn(out long blah, out long blah2);

class sealed ClassBlah
{
private ClassBlah()
{
}

}
}

Why have I to call this with the CallingConvention of ThisCall, its just
normal "C" functions in a DLL. Why wont StdCall work?

What happens with other calling conventions is that the out parameters are
NOT set, yet with ThisCall, they are set ok, or appear to be. I find it odd.

Thanks

[Nicholas Paldino [.NET/C# MVP]]

Mr. Tickle,

What is the declaration of the original function? If it takes a
pointer, then you should be using "ref" for the parameters, and not out.
Also, does the function take a 64-bit integer? Long in C is a 32-bit
integer, where in .NET it is a 64-bit integer.

The STDCALL mechanism should work if you are using it.

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- ni**************@exisconsulting.com

"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:Oo**************@TK2MSFTNGP09.phx.gbl...

I am calling an unmanaged DLL like follows in a Class wrapper.

namespace blah
{
[DllImport("DLLName.DLL", EntryPoint="BlahEntryPoint",
CallingConvention=CallingConvention.ThisCall]
public static extern void blahFn(out long blah, out long blah2);

class sealed ClassBlah
{
private ClassBlah()
{
}

}
}

Why have I to call this with the CallingConvention of ThisCall, its just
normal "C" functions in a DLL. Why wont StdCall work?

What happens with other calling conventions is that the out parameters are
NOT set, yet with ThisCall, they are set ok, or appear to be. I find it odd.
Thanks

[Mr.Tickle]

Nop, I tried ref and it doesnt help, the only way i can get it to return
values is with thiscall.

"Nicholas Paldino [.NET/C# MVP]" <ni**************@exisconsulting.com> wrote
in message news:#p**************@TK2MSFTNGP11.phx.gbl...

Mr. Tickle,

What is the declaration of the original function? If it takes a
pointer, then you should be using "ref" for the parameters, and not out.
Also, does the function take a 64-bit integer? Long in C is a 32-bit
integer, where in .NET it is a 64-bit integer.

The STDCALL mechanism should work if you are using it.

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- ni**************@exisconsulting.com

"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:Oo**************@TK2MSFTNGP09.phx.gbl...

I am calling an unmanaged DLL like follows in a Class wrapper.

namespace blah
{
[DllImport("DLLName.DLL", EntryPoint="BlahEntryPoint",
CallingConvention=CallingConvention.ThisCall]
public static extern void blahFn(out long blah, out long blah2);

class sealed ClassBlah
{
private ClassBlah()
{
}

}
}

Why have I to call this with the CallingConvention of ThisCall, its just normal "C" functions in a DLL. Why wont StdCall work?

What happens with other calling conventions is that the out parameters are NOT set, yet with ThisCall, they are set ok, or appear to be. I find it

odd.

Thanks

[Mr.Tickle]

So i should use Int32 for the parameters instead of long?
"Nicholas Paldino [.NET/C# MVP]" <ni**************@exisconsulting.com> wrote
in message news:#p**************@TK2MSFTNGP11.phx.gbl...

Mr. Tickle,

What is the declaration of the original function? If it takes a
pointer, then you should be using "ref" for the parameters, and not out.
Also, does the function take a 64-bit integer? Long in C is a 32-bit
integer, where in .NET it is a 64-bit integer.

The STDCALL mechanism should work if you are using it.

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- ni**************@exisconsulting.com

"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:Oo**************@TK2MSFTNGP09.phx.gbl...

I am calling an unmanaged DLL like follows in a Class wrapper.

namespace blah
{
[DllImport("DLLName.DLL", EntryPoint="BlahEntryPoint",
CallingConvention=CallingConvention.ThisCall]
public static extern void blahFn(out long blah, out long blah2);

class sealed ClassBlah
{
private ClassBlah()
{
}

}
}

Why have I to call this with the CallingConvention of ThisCall, its just normal "C" functions in a DLL. Why wont StdCall work?

What happens with other calling conventions is that the out parameters are NOT set, yet with ThisCall, they are set ok, or appear to be. I find it

odd.

Thanks

[Mr.Tickle]

I also have a problem with "ref" paramaters, it says they need to be
assigned to before used

Yet i have them used as "ref" in dll extern calls and checked for non NULL
after yet it complains for non assignment so i use a local copy.

Isnt it smart enough to detect that its being assinged in an extern dll call
as declared in DllImport?


"Nicholas Paldino [.NET/C# MVP]" <ni**************@exisconsulting.com> wrote
in message news:#p**************@TK2MSFTNGP11.phx.gbl...

Mr. Tickle,

What is the declaration of the original function? If it takes a
pointer, then you should be using "ref" for the parameters, and not out.
Also, does the function take a 64-bit integer? Long in C is a 32-bit
integer, where in .NET it is a 64-bit integer.

The STDCALL mechanism should work if you are using it.

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- ni**************@exisconsulting.com

"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:Oo**************@TK2MSFTNGP09.phx.gbl...

I am calling an unmanaged DLL like follows in a Class wrapper.

namespace blah
{
[DllImport("DLLName.DLL", EntryPoint="BlahEntryPoint",
CallingConvention=CallingConvention.ThisCall]
public static extern void blahFn(out long blah, out long blah2);

class sealed ClassBlah
{
private ClassBlah()
{
}

}
}

Why have I to call this with the CallingConvention of ThisCall, its just normal "C" functions in a DLL. Why wont StdCall work?

What happens with other calling conventions is that the out parameters are NOT set, yet with ThisCall, they are set ok, or appear to be. I find it

odd.

Thanks

[Mr.Tickle]

i mean "out" oops.

ref in the same dll wrapper still gets the output but only with thiscall
convention.
"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:OQ**************@TK2MSFTNGP09.phx.gbl...

I also have a problem with "ref" paramaters, it says they need to be
assigned to before used

Yet i have them used as "ref" in dll extern calls and checked for non NULL
after yet it complains for non assignment so i use a local copy.

Isnt it smart enough to detect that its being assinged in an extern dll call as declared in DllImport?


"Nicholas Paldino [.NET/C# MVP]" <ni**************@exisconsulting.com> wrote in message news:#p**************@TK2MSFTNGP11.phx.gbl...

Mr. Tickle,

What is the declaration of the original function? If it takes a
pointer, then you should be using "ref" for the parameters, and not out.
Also, does the function take a 64-bit integer? Long in C is a 32-bit
integer, where in .NET it is a 64-bit integer.

The STDCALL mechanism should work if you are using it.

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- ni**************@exisconsulting.com

"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:Oo**************@TK2MSFTNGP09.phx.gbl...

I am calling an unmanaged DLL like follows in a Class wrapper.

namespace blah
{
[DllImport("DLLName.DLL", EntryPoint="BlahEntryPoint",
CallingConvention=CallingConvention.ThisCall]
public static extern void blahFn(out long blah, out long blah2);

class sealed ClassBlah
{
private ClassBlah()
{
}

}
}

Why have I to call this with the CallingConvention of ThisCall, its just normal "C" functions in a DLL. Why wont StdCall work?

What happens with other calling conventions is that the out parameters are NOT set, yet with ThisCall, they are set ok, or appear to be. I find

it odd.

Thanks

[Nicholas Paldino [.NET/C# MVP]]

If you could post the original function declaration, it would help
tremendously.
--
- Nicholas Paldino [.NET/C# MVP]
- ni**************@exisconsulting.com

"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:e6**************@TK2MSFTNGP09.phx.gbl...

i mean "out" oops.

ref in the same dll wrapper still gets the output but only with thiscall
convention.
"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:OQ**************@TK2MSFTNGP09.phx.gbl...

I also have a problem with "ref" paramaters, it says they need to be
assigned to before used

Yet i have them used as "ref" in dll extern calls and checked for non NULL

after yet it complains for non assignment so i use a local copy.

Isnt it smart enough to detect that its being assinged in an extern dll

call

as declared in DllImport?


"Nicholas Paldino [.NET/C# MVP]" <ni**************@exisconsulting.com>

wrote

in message news:#p**************@TK2MSFTNGP11.phx.gbl...

Mr. Tickle,

What is the declaration of the original function? If it takes a
pointer, then you should be using "ref" for the parameters, and not out. Also, does the function take a 64-bit integer? Long in C is a 32-bit
integer, where in .NET it is a 64-bit integer.

The STDCALL mechanism should work if you are using it.

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- ni**************@exisconsulting.com

"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:Oo**************@TK2MSFTNGP09.phx.gbl...
> I am calling an unmanaged DLL like follows in a Class wrapper.
>
> namespace blah
> {
> [DllImport("DLLName.DLL", EntryPoint="BlahEntryPoint",
> CallingConvention=CallingConvention.ThisCall]
> public static extern void blahFn(out long blah, out long blah2);
>
> class sealed ClassBlah
> {
> private ClassBlah()
> {
> }
>
> }
> }
>
> Why have I to call this with the CallingConvention of ThisCall, its

just

> normal "C" functions in a DLL. Why wont StdCall work?
>
> What happens with other calling conventions is that the out

parameters are

> NOT set, yet with ThisCall, they are set ok, or appear to be. I find

it odd.
>
>
>
> Thanks
>
>

[Mr.Tickle]

It would but I dont have it, its in a dll i have to call into. Not mine.


"Nicholas Paldino [.NET/C# MVP]" <ni**************@exisconsulting.com> wrote
in message news:OB**************@TK2MSFTNGP11.phx.gbl...

If you could post the original function declaration, it would help
tremendously.
--
- Nicholas Paldino [.NET/C# MVP]
- ni**************@exisconsulting.com

"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:e6**************@TK2MSFTNGP09.phx.gbl...

i mean "out" oops.

ref in the same dll wrapper still gets the output but only with thiscall
convention.
"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:OQ**************@TK2MSFTNGP09.phx.gbl...

I also have a problem with "ref" paramaters, it says they need to be
assigned to before used

Yet i have them used as "ref" in dll extern calls and checked for non NULL after yet it complains for non assignment so i use a local copy.

Isnt it smart enough to detect that its being assinged in an extern dll

call

as declared in DllImport?


"Nicholas Paldino [.NET/C# MVP]" <ni**************@exisconsulting.com>

wrote

in message news:#p**************@TK2MSFTNGP11.phx.gbl...
> Mr. Tickle,
>
> What is the declaration of the original function? If it takes a
> pointer, then you should be using "ref" for the parameters, and not out. > Also, does the function take a 64-bit integer? Long in C is a

32-bit > integer, where in .NET it is a 64-bit integer.
>
> The STDCALL mechanism should work if you are using it.
>
> Hope this helps.
>
>
> --
> - Nicholas Paldino [.NET/C# MVP]
> - ni**************@exisconsulting.com
>
> "Mr.Tickle" <Mr******@mrmen.com> wrote in message
> news:Oo**************@TK2MSFTNGP09.phx.gbl...
> > I am calling an unmanaged DLL like follows in a Class wrapper.
> >
> > namespace blah
> > {
> > [DllImport("DLLName.DLL", EntryPoint="BlahEntryPoint",
> > CallingConvention=CallingConvention.ThisCall]
> > public static extern void blahFn(out long blah, out long blah2);
> >
> > class sealed ClassBlah
> > {
> > private ClassBlah()
> > {
> > }
> >
> > }
> > }
> >
> > Why have I to call this with the CallingConvention of ThisCall, its just
> > normal "C" functions in a DLL. Why wont StdCall work?
> >
> > What happens with other calling conventions is that the out parameters are
> > NOT set, yet with ThisCall, they are set ok, or appear to be. I

find it

> odd.
> >
> >
> >
> > Thanks
> >
> >
>
>

[Mr.Tickle]

typedef SOME_ID long

SOME_ID someFn(SOME_ID* someIDhere, SOME_ID* someIDhere2, SOME_ID*
someIDhere3);

something like that.
"Nicholas Paldino [.NET/C# MVP]" <ni**************@exisconsulting.com> wrote
in message news:OB**************@TK2MSFTNGP11.phx.gbl...

If you could post the original function declaration, it would help
tremendously.
--
- Nicholas Paldino [.NET/C# MVP]
- ni**************@exisconsulting.com

"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:e6**************@TK2MSFTNGP09.phx.gbl...

i mean "out" oops.

ref in the same dll wrapper still gets the output but only with thiscall
convention.
"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:OQ**************@TK2MSFTNGP09.phx.gbl...

I also have a problem with "ref" paramaters, it says they need to be
assigned to before used

Yet i have them used as "ref" in dll extern calls and checked for non NULL after yet it complains for non assignment so i use a local copy.

Isnt it smart enough to detect that its being assinged in an extern dll

call

as declared in DllImport?


"Nicholas Paldino [.NET/C# MVP]" <ni**************@exisconsulting.com>

wrote

in message news:#p**************@TK2MSFTNGP11.phx.gbl...
> Mr. Tickle,
>
> What is the declaration of the original function? If it takes a
> pointer, then you should be using "ref" for the parameters, and not out. > Also, does the function take a 64-bit integer? Long in C is a

32-bit > integer, where in .NET it is a 64-bit integer.
>
> The STDCALL mechanism should work if you are using it.
>
> Hope this helps.
>
>
> --
> - Nicholas Paldino [.NET/C# MVP]
> - ni**************@exisconsulting.com
>
> "Mr.Tickle" <Mr******@mrmen.com> wrote in message
> news:Oo**************@TK2MSFTNGP09.phx.gbl...
> > I am calling an unmanaged DLL like follows in a Class wrapper.
> >
> > namespace blah
> > {
> > [DllImport("DLLName.DLL", EntryPoint="BlahEntryPoint",
> > CallingConvention=CallingConvention.ThisCall]
> > public static extern void blahFn(out long blah, out long blah2);
> >
> > class sealed ClassBlah
> > {
> > private ClassBlah()
> > {
> > }
> >
> > }
> > }
> >
> > Why have I to call this with the CallingConvention of ThisCall, its just
> > normal "C" functions in a DLL. Why wont StdCall work?
> >
> > What happens with other calling conventions is that the out parameters are
> > NOT set, yet with ThisCall, they are set ok, or appear to be. I

find it

> odd.
> >
> >
> >
> > Thanks
> >
> >
>
>

[Nicholas Paldino [.NET/C# MVP]]

Mr.Tickle,

In this case, you definitely want to use the int type, and pass it by
reference. Your declaration should look like this:

[DllImport("somedll.dll")]
public static extern int someFn(ref int someIDhere, ref int someIDhere2, ref
int someIDhere3);
--
- Nicholas Paldino [.NET/C# MVP]
- ni**************@exisconsulting.com

"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:%2****************@tk2msftngp13.phx.gbl...

typedef SOME_ID long

SOME_ID someFn(SOME_ID* someIDhere, SOME_ID* someIDhere2, SOME_ID*
someIDhere3);

something like that.
"Nicholas Paldino [.NET/C# MVP]" <ni**************@exisconsulting.com> wrote in message news:OB**************@TK2MSFTNGP11.phx.gbl...

If you could post the original function declaration, it would help
tremendously.
--
- Nicholas Paldino [.NET/C# MVP]
- ni**************@exisconsulting.com

"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:e6**************@TK2MSFTNGP09.phx.gbl...

i mean "out" oops.

ref in the same dll wrapper still gets the output but only with thiscall convention.
"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:OQ**************@TK2MSFTNGP09.phx.gbl...
> I also have a problem with "ref" paramaters, it says they need to be
> assigned to before used
>
> Yet i have them used as "ref" in dll extern calls and checked for non

NULL

> after yet it complains for non assignment so i use a local copy.
>
> Isnt it smart enough to detect that its being assinged in an extern dll call
> as declared in DllImport?
>
>
>
>
> "Nicholas Paldino [.NET/C# MVP]"

<ni**************@exisconsulting.com> wrote
> in message news:#p**************@TK2MSFTNGP11.phx.gbl...
> > Mr. Tickle,
> >
> > What is the declaration of the original function? If it takes a > > pointer, then you should be using "ref" for the parameters, and not

out.

> > Also, does the function take a 64-bit integer? Long in C is a

32-bit > > integer, where in .NET it is a 64-bit integer.
> >
> > The STDCALL mechanism should work if you are using it.
> >
> > Hope this helps.
> >
> >
> > --
> > - Nicholas Paldino [.NET/C# MVP]
> > - ni**************@exisconsulting.com
> >
> > "Mr.Tickle" <Mr******@mrmen.com> wrote in message
> > news:Oo**************@TK2MSFTNGP09.phx.gbl...
> > > I am calling an unmanaged DLL like follows in a Class wrapper.
> > >
> > > namespace blah
> > > {
> > > [DllImport("DLLName.DLL", EntryPoint="BlahEntryPoint",
> > > CallingConvention=CallingConvention.ThisCall]
> > > public static extern void blahFn(out long blah, out long

blah2); > > >
> > > class sealed ClassBlah
> > > {
> > > private ClassBlah()
> > > {
> > > }
> > >
> > > }
> > > }
> > >
> > > Why have I to call this with the CallingConvention of ThisCall,

its > just
> > > normal "C" functions in a DLL. Why wont StdCall work?
> > >
> > > What happens with other calling conventions is that the out

parameters

> are
> > > NOT set, yet with ThisCall, they are set ok, or appear to be. I find it
> > odd.
> > >
> > >
> > >
> > > Thanks
> > >
> > >
> >
> >
>
>

[Mr.Tickle]

But I still dont understand why Thiscall works and the others dont.
"Nicholas Paldino [.NET/C# MVP]" <ni**************@exisconsulting.com> wrote
in message news:uv**************@TK2MSFTNGP10.phx.gbl...

Mr.Tickle,

In this case, you definitely want to use the int type, and pass it by
reference. Your declaration should look like this:

[DllImport("somedll.dll")]
public static extern int someFn(ref int someIDhere, ref int someIDhere2, ref int someIDhere3);
--
- Nicholas Paldino [.NET/C# MVP]
- ni**************@exisconsulting.com

"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:%2****************@tk2msftngp13.phx.gbl...

typedef SOME_ID long

SOME_ID someFn(SOME_ID* someIDhere, SOME_ID* someIDhere2, SOME_ID*
someIDhere3);

something like that.
"Nicholas Paldino [.NET/C# MVP]" <ni**************@exisconsulting.com> wrote

in message news:OB**************@TK2MSFTNGP11.phx.gbl...

If you could post the original function declaration, it would help
tremendously.
--
- Nicholas Paldino [.NET/C# MVP]
- ni**************@exisconsulting.com

"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:e6**************@TK2MSFTNGP09.phx.gbl...
> i mean "out" oops.
>
> ref in the same dll wrapper still gets the output but only with thiscall > convention.
>
>
> "Mr.Tickle" <Mr******@mrmen.com> wrote in message
> news:OQ**************@TK2MSFTNGP09.phx.gbl...
> > I also have a problem with "ref" paramaters, it says they need to be > > assigned to before used
> >
> > Yet i have them used as "ref" in dll extern calls and checked for non NULL
> > after yet it complains for non assignment so i use a local copy.
> >
> > Isnt it smart enough to detect that its being assinged in an exter

n

dll

> call
> > as declared in DllImport?
> >
> >
> >
> >
> > "Nicholas Paldino [.NET/C# MVP]" <ni**************@exisconsulting.com> > wrote
> > in message news:#p**************@TK2MSFTNGP11.phx.gbl...
> > > Mr. Tickle,
> > >
> > > What is the declaration of the original function? If it

takes a > > > pointer, then you should be using "ref" for the parameters, and not out.
> > > Also, does the function take a 64-bit integer? Long in C is a

32-bit

> > > integer, where in .NET it is a 64-bit integer.
> > >
> > > The STDCALL mechanism should work if you are using it.
> > >
> > > Hope this helps.
> > >
> > >
> > > --
> > > - Nicholas Paldino [.NET/C# MVP]
> > > - ni**************@exisconsulting.com
> > >
> > > "Mr.Tickle" <Mr******@mrmen.com> wrote in message
> > > news:Oo**************@TK2MSFTNGP09.phx.gbl...
> > > > I am calling an unmanaged DLL like follows in a Class wrapper.
> > > >
> > > > namespace blah
> > > > {
> > > > [DllImport("DLLName.DLL", EntryPoint="BlahEntryPoint",
> > > > CallingConvention=CallingConvention.ThisCall]
> > > > public static extern void blahFn(out long blah, out long blah2); > > > >
> > > > class sealed ClassBlah
> > > > {
> > > > private ClassBlah()
> > > > {
> > > > }
> > > >
> > > > }
> > > > }
> > > >
> > > > Why have I to call this with the CallingConvention of

ThisCall, its

> > just
> > > > normal "C" functions in a DLL. Why wont StdCall work?
> > > >
> > > > What happens with other calling conventions is that the out
parameters
> > are
> > > > NOT set, yet with ThisCall, they are set ok, or appear to be.

I find

> it
> > > odd.
> > > >
> > > >
> > > >
> > > > Thanks
> > > >
> > > >
> > >
> > >
> >
> >
>
>

[Willy Denoyette [MVP]]

Because in you definition you only pass two arguments, while you need tree (an int, and to poiters).
It works while using the thiscall calling convention, because the interop layer passes as first argument an int for the this pointer
(three int's are reserved on the stack).

Willy.

"Mr.Tickle" <Mr******@mrmen.com> wrote in message news:%2****************@tk2msftngp13.phx.gbl...

But I still dont understand why Thiscall works and the others dont.
"Nicholas Paldino [.NET/C# MVP]" <ni**************@exisconsulting.com> wrote
in message news:uv**************@TK2MSFTNGP10.phx.gbl...

Mr.Tickle,

In this case, you definitely want to use the int type, and pass it by
reference. Your declaration should look like this:

[DllImport("somedll.dll")]
public static extern int someFn(ref int someIDhere, ref int someIDhere2,

ref

int someIDhere3);
--
- Nicholas Paldino [.NET/C# MVP]
- ni**************@exisconsulting.com

"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:%2****************@tk2msftngp13.phx.gbl...

typedef SOME_ID long

SOME_ID someFn(SOME_ID* someIDhere, SOME_ID* someIDhere2, SOME_ID*
someIDhere3);

something like that.
"Nicholas Paldino [.NET/C# MVP]" <ni**************@exisconsulting.com>

wrote

in message news:OB**************@TK2MSFTNGP11.phx.gbl...
> If you could post the original function declaration, it would help
> tremendously.
>
>
> --
> - Nicholas Paldino [.NET/C# MVP]
> - ni**************@exisconsulting.com
>
> "Mr.Tickle" <Mr******@mrmen.com> wrote in message
> news:e6**************@TK2MSFTNGP09.phx.gbl...
> > i mean "out" oops.
> >
> > ref in the same dll wrapper still gets the output but only with

thiscall

> > convention.
> >
> >
> > "Mr.Tickle" <Mr******@mrmen.com> wrote in message
> > news:OQ**************@TK2MSFTNGP09.phx.gbl...
> > > I also have a problem with "ref" paramaters, it says they need to be > > > assigned to before used
> > >
> > > Yet i have them used as "ref" in dll extern calls and checked for

non

> NULL
> > > after yet it complains for non assignment so i use a local copy.
> > >
> > > Isnt it smart enough to detect that its being assinged in an exter n dll
> > call
> > > as declared in DllImport?
> > >
> > >
> > >
> > >
> > > "Nicholas Paldino [.NET/C# MVP]"

<ni**************@exisconsulting.com>

> > wrote
> > > in message news:#p**************@TK2MSFTNGP11.phx.gbl...
> > > > Mr. Tickle,
> > > >
> > > > What is the declaration of the original function? If it takes

a

> > > > pointer, then you should be using "ref" for the parameters, and

not

> out.
> > > > Also, does the function take a 64-bit integer? Long in C is a
32-bit
> > > > integer, where in .NET it is a 64-bit integer.
> > > >
> > > > The STDCALL mechanism should work if you are using it.
> > > >
> > > > Hope this helps.
> > > >
> > > >
> > > > --
> > > > - Nicholas Paldino [.NET/C# MVP]
> > > > - ni**************@exisconsulting.com
> > > >
> > > > "Mr.Tickle" <Mr******@mrmen.com> wrote in message
> > > > news:Oo**************@TK2MSFTNGP09.phx.gbl...
> > > > > I am calling an unmanaged DLL like follows in a Class wrapper.
> > > > >
> > > > > namespace blah
> > > > > {
> > > > > [DllImport("DLLName.DLL", EntryPoint="BlahEntryPoint",
> > > > > CallingConvention=CallingConvention.ThisCall]
> > > > > public static extern void blahFn(out long blah, out long

blah2);

> > > > >
> > > > > class sealed ClassBlah
> > > > > {
> > > > > private ClassBlah()
> > > > > {
> > > > > }
> > > > >
> > > > > }
> > > > > }
> > > > >
> > > > > Why have I to call this with the CallingConvention of

ThisCall, its
> > > just
> > > > > normal "C" functions in a DLL. Why wont StdCall work?
> > > > >
> > > > > What happens with other calling conventions is that the out
> parameters
> > > are
> > > > > NOT set, yet with ThisCall, they are set ok, or appear to be. I find
> > it
> > > > odd.
> > > > >
> > > > >
> > > > >
> > > > > Thanks
> > > > >
> > > > >
> > > >
> > > >
> > >
> > >
> >
> >
>
>

[Mr.Tickle]

Well its suppost to match up, its just something i typed in a hurry but it
is the same number of arguments in the definition and call. on teh real
code.
the dll definition would be

typedef SOMEVAL long
typedef SOME_ID long

SOME_ID someFn(SOMEVAL someVal, SOME_ID* someIDhere, SOME_ID* someIDhere2,
SOME_ID* someIDhere3);
so im calling with for example out of my memory

DllImport("somedll.dll", EntryPoint="blahFn",
CallingConvention=CallingConvention.ThisCall)]
public static extern int someFn(long someVal, ref someIDhere, ref long
someIDhere2, ref long someIDhere3);
// i know this should be int instead of long but curious why the long works
with thiscall and not the others or just not work at all.

long someVal;
long ID someID,
anotherID,
yetAnohterID,
andAnotherID;

someID = blahFn(someVal, ref anotherID, ref yetAnotherID, ref andAnotherID);

Only thiscall works, others dont, so if i understand it right I change the
definition from long to int for 32bit instead of the 64bit on the .net side,
and then i can use stdcall as normal.


"Willy Denoyette [MVP]" <wi*************@pandora.be> wrote in message
news:OE**************@tk2msftngp13.phx.gbl...

Because in you definition you only pass two arguments, while you need tree (an int, and to poiters). It works while using the thiscall calling convention, because the interop layer passes as first argument an int for the this pointer (three int's are reserved on the stack).

Willy.

"Mr.Tickle" <Mr******@mrmen.com> wrote in message

news:%2****************@tk2msftngp13.phx.gbl...

But I still dont understand why Thiscall works and the others dont.
"Nicholas Paldino [.NET/C# MVP]" <ni**************@exisconsulting.com> wrote in message news:uv**************@TK2MSFTNGP10.phx.gbl...

Mr.Tickle,

In this case, you definitely want to use the int type, and pass it by reference. Your declaration should look like this:

[DllImport("somedll.dll")]
public static extern int someFn(ref int someIDhere, ref int someIDhere2,

ref

int someIDhere3);
--
- Nicholas Paldino [.NET/C# MVP]
- ni**************@exisconsulting.com

"Mr.Tickle" <Mr******@mrmen.com> wrote in message
news:%2****************@tk2msftngp13.phx.gbl...
> typedef SOME_ID long
>
> SOME_ID someFn(SOME_ID* someIDhere, SOME_ID* someIDhere2, SOME_ID*
> someIDhere3);
>
> something like that.
>
>
> "Nicholas Paldino [.NET/C# MVP]"

<ni**************@exisconsulting.com> wrote
> in message news:OB**************@TK2MSFTNGP11.phx.gbl...
> > If you could post the original function declaration, it would help > > tremendously.
> >
> >
> > --
> > - Nicholas Paldino [.NET/C# MVP]
> > - ni**************@exisconsulting.com
> >
> > "Mr.Tickle" <Mr******@mrmen.com> wrote in message
> > news:e6**************@TK2MSFTNGP09.phx.gbl...
> > > i mean "out" oops.
> > >
> > > ref in the same dll wrapper still gets the output but only with
thiscall
> > > convention.
> > >
> > >
> > > "Mr.Tickle" <Mr******@mrmen.com> wrote in message
> > > news:OQ**************@TK2MSFTNGP09.phx.gbl...
> > > > I also have a problem with "ref" paramaters, it says they need to be

> > > > assigned to before used
> > > >
> > > > Yet i have them used as "ref" in dll extern calls and checked

for non
> > NULL
> > > > after yet it complains for non assignment so i use a local copy. > > > >
> > > > Isnt it smart enough to detect that its being assinged in an exter n

> dll
> > > call
> > > > as declared in DllImport?
> > > >
> > > >
> > > >
> > > >
> > > > "Nicholas Paldino [.NET/C# MVP]"
<ni**************@exisconsulting.com>
> > > wrote
> > > > in message news:#p**************@TK2MSFTNGP11.phx.gbl...
> > > > > Mr. Tickle,
> > > > >
> > > > > What is the declaration of the original function? If it

takes

a
> > > > > pointer, then you should be using "ref" for the parameters,

and not
> > out.
> > > > > Also, does the function take a 64-bit integer? Long in C is a > 32-bit
> > > > > integer, where in .NET it is a 64-bit integer.
> > > > >
> > > > > The STDCALL mechanism should work if you are using it.
> > > > >
> > > > > Hope this helps.
> > > > >
> > > > >
> > > > > --
> > > > > - Nicholas Paldino [.NET/C# MVP]
> > > > > - ni**************@exisconsulting.com
> > > > >
> > > > > "Mr.Tickle" <Mr******@mrmen.com> wrote in message
> > > > > news:Oo**************@TK2MSFTNGP09.phx.gbl...
> > > > > > I am calling an unmanaged DLL like follows in a Class wrapper. > > > > > >
> > > > > > namespace blah
> > > > > > {
> > > > > > [DllImport("DLLName.DLL", EntryPoint="BlahEntryPoint",
> > > > > > CallingConvention=CallingConvention.ThisCall]
> > > > > > public static extern void blahFn(out long blah, out long
blah2);
> > > > > >
> > > > > > class sealed ClassBlah
> > > > > > {
> > > > > > private ClassBlah()
> > > > > > {
> > > > > > }
> > > > > >
> > > > > > }
> > > > > > }
> > > > > >
> > > > > > Why have I to call this with the CallingConvention of

ThisCall,

> its
> > > > just
> > > > > > normal "C" functions in a DLL. Why wont StdCall work?
> > > > > >
> > > > > > What happens with other calling conventions is that the out > > parameters
> > > > are
> > > > > > NOT set, yet with ThisCall, they are set ok, or appear to

be. I

> find
> > > it
> > > > > odd.
> > > > > >
> > > > > >
> > > > > >
> > > > > > Thanks
> > > > > >
> > > > > >
> > > > >
> > > > >
> > > >
> > > >
> > >
> > >
> >
> >
>
>