Re: [Swig-user] how to type cast pointers for CSharp using SWIG?

[David P. <dpi...@me...>]

>  In my c++ project most of the functions having pointers as input like int* ,
> float * ,double * ,As CSharp doesn't support pointers  and passing pointers to
> function in c+ means parameter must returning value in its out parameter .
> 
> so to make pointer as out , i typecast the pointers using following code in my
> interface file.
> 
> %define INOUT_TYPEMAP(TYPE, CTYPE, CSTYPE, TYPECHECKPRECEDENCE)
> 
> %typemap(ctype) TYPE *, TYPE & "CTYPE *"
> %typemap(imtype) TYPE *, TYPE & "out CSTYPE"
> %typemap(cstype) TYPE *, TYPE & "out CSTYPE"
> %typemap(csin) TYPE *, TYPE & "out $csinput"
> %typemap(in) TYPE *, TYPE &
> %{ $1 = ($1_ltype)$input; %}
> 
> %typecheck(SWIG_TYPECHECK_##TYPECHECKPRECEDENCE) TYPE *INOUT,
> TYPE &INOUT ""
> %enddef
....
> After all this changes my pointers is now converted into out as parameter .
> 
> But if my C++ function is like
> 
> int* Function(int* a ,int b);
> 
> then generated C# function will become
> 
> out int Function(out int a, int b) ..............return parameter also becomes out
> and this is not a legal statement in c#.

You need to use the "out" attribute of the "cstype" and "imtype" typemaps:

%typemap(imtype, out="CSTYPE") TYPE *, TYPE & "out CSTYPE"
%typemap(cstype, out="CSTYPE") TYPE *, TYPE & "out CSTYPE"

Also, you may find the attached document helpful.