DLLImport and Marshalling

[Simon]

Hi all,

I am trying to call a function from a dll and it has the following
prototype.

int foo(int *argc, char ***argv) or int foo(int *argc, char *argv[])

I am having problems that I assume are to do with marshalling. I am
using

[DllImport("some.dll")]
int foo(IntPtr argc, string[] argv)

But this is failing. Am I missing something somewhere? Am I making a
blindingly obvious mistake.

TIA for your help.

Simon

 

[Dmytro Lapshyn [MVP]]

Hey Simon,

First of all, this should at least be:

[DllImport("some.dll")]
int foo(ref int argc, string[] argv)

As for the second argument, can you please check that the C++ declaration is

int foo(int *argc, char ***argv)

or still

int foo(int *argc, char **argv) ?

--
Sincerely,
Dmytro Lapshyn [Visual Developer - Visual C# MVP]

Hi all,

I am trying to call a function from a dll and it has the following
prototype.

int foo(int *argc, char ***argv) or int foo(int *argc, char *argv[])

I am having problems that I assume are to do with marshalling. I am
using

[DllImport("some.dll")]
int foo(IntPtr argc, string[] argv)

But this is failing. Am I missing something somewhere? Am I making a
blindingly obvious mistake.

TIA for your help.

Simon

 

[s.p.nee]

Thanks for the quick reply Dmytro.

Yes the declaration is definitely.

int foo(int *argc, char ***argv) .

It is the initialization funtion of the MPI library, the following it
cut and paste from the header.

int MPI_Init(int *argc, char ***argv)

Thanks

Simon

 

[s.p.nee]

Thanks I have now solved this with Dmytro's pointing me in the right
direction.

For those interested. The answer to my problem was

[DllImport("mpich.dll", EntryPoint="MPI_Init")]
private static extern int MPI_Init(ref int argc , ref string[] arg);

Thanks Dmytro.

Simon