Original bug ID: 426
Reporter: administrator
Status: closed
Resolution: fixed
Priority: normal
Severity: minor
Category: -for CamlIDL use https://github.com/xavierleroy/camlidl/issues

Bug description

Full_Name: Dmitry Bely
Version: camlidl current cvs
OS: Windows NT 4.0
Submission from: d227.p3.col.ru (195.210.132.227)

Let's consider the following example:

[---cut---]
void f();

[object]
interface ITest: IUnknown
{
void method();
}
[---cut---]

It produces cplusplus.h file which we are going to use in C++ mode:

[---cut---]
/* File generated from cplusplus.idl */

#ifndef _CAMLIDL_CPLUSPLUS_H
#define _CAMLIDL_CPLUSPLUS_H

extern void f(void); /* (1) */

struct ITest;
#ifdef __cplusplus
struct ITest {
virtual HRESULT (STDMETHODCALLTYPE *QueryInterface)(IID *, void **);
virtual ULONG (STDMETHODCALLTYPE *AddRef)();
virtual ULONG (STDMETHODCALLTYPE *Release)();
virtual void (STDMETHODCALLTYPE method)(); / (2) */
};
#else
struct ITestVtbl {
DECLARE_VTBL_PADDING
HRESULT (STDMETHODCALLTYPE *QueryInterface)(struct ITest *, IID *, void **);
ULONG (STDMETHODCALLTYPE *AddRef)(struct ITest *);
ULONG (STDMETHODCALLTYPE *Release)(struct ITest *);
void (STDMETHODCALLTYPE method)(struct ITest * self);
};
struct ITest {
struct ITestVtbl * lpVtbl;
};
#endif
extern IID IID_ITest; / (3) */

#endif /* !_CAMLIDL_CPLUSPLUS_H */
[---cut---]

(1,3) Extern variables and functions should be declared as 'extern "C"' in c++
mode.
(2) Syntax error -- should be "virtual void STDMETHODCALLTYPE method();"

Also when we generate code for Win32, proper COM-compatible alignment should be
specified.

So the following path is proposed:

[---cut---]
Index: compiler/file.ml

RCS file: /caml/bazar-ocaml/camlidl/compiler/file.ml,v
retrieving revision 1.16
diff -u -r1.16 file.ml
--- compiler/file.ml 2001/06/15 16:53:45 1.16
+++ compiler/file.ml 2001/07/09 13:43:25
@@ -216,8 +216,21 @@
fprintf oc "
#ifndef %s\n
#define %s\n\n" symbname symbname;

• fprintf oc "\
• #ifdef __cplusplus\n\
• #define _CAMLIDL_EXTERN_C extern "C"\n\
• #else\n\
• #define _CAMLIDL_EXTERN_C extern\n\
• #endif\n\n\
• #ifdef _WIN32\n\
• #pragma pack(push,8) /* is necessary for COM interfaces */\n\
• #endif\n\n";
  (* Emit the definitions *)
  List.iter (process_definition oc) intf;
• fprintf oc "\
• #ifdef _WIN32\n\
• #pragma pack(pop)\n\
• #endif\n\n";
  fprintf oc "\n
  #endif /* !%s */\n" symbname

Index: compiler/funct.ml

RCS file: /caml/bazar-ocaml/camlidl/compiler/funct.ml,v
retrieving revision 1.25
diff -u -r1.25 funct.ml
--- compiler/funct.ml 2001/06/17 10:50:25 1.25
+++ compiler/funct.ml 2001/07/09 13:43:27
@@ -114,7 +114,7 @@
(* Generate the C declaration for a function *)

let c_declaration oc fundecl =

• fprintf oc "extern %a(" out_c_decl (fundecl.fun_name, fundecl.fun_res);

• fprintf oc "_CAMLIDL_EXTERN_C %a(" out_c_decl (fundecl.fun_name,
  fundecl.fun_res);
  begin match fundecl.fun_params with
  [] -> fprintf oc "void"
  | p1 :: pl ->
  Index: compiler/intf.ml
  ===================================================================
  RCS file: /caml/bazar-ocaml/camlidl/compiler/intf.ml,v
  retrieving revision 1.20
  diff -u -r1.20 intf.ml
  --- compiler/intf.ml 2001/06/17 10:50:25 1.20
  +++ compiler/intf.ml 2001/07/09 13:43:31
  @@ -122,7 +122,7 @@
  List.iter
  (fun m ->
  iprintf oc "virtual %a("

•               out_c_decl (sprintf "(STDMETHODCALLTYPE *%s)" m.fun_name,
  

•               out_c_decl (sprintf "STDMETHODCALLTYPE %s" m.fun_name,
                            m.fun_res);
     let first = ref true in
     List.iter
  

@@ -153,7 +153,7 @@
fprintf oc " struct %sVtbl * lpVtbl;\n" intf.intf_name;
fprintf oc "};\n";
fprintf oc "#endif\n";

• fprintf oc "extern IID IID_%s;\n\n" intf.intf_name

• fprintf oc "CAMLIDL_EXTERN_C IID IID%s;\n\n" intf.intf_name
  end

(* Define the wrapper classes *)
[---cut---]

and now we have

[---cut---]
/* File generated from cplusplus.idl */

#ifndef _CAMLIDL_CPLUSPLUS_H
#define _CAMLIDL_CPLUSPLUS_H

#ifdef __cplusplus
#define _CAMLIDL_EXTERN_C extern "C"
#else
#define _CAMLIDL_EXTERN_C extern
#endif

#ifdef _WIN32
#pragma pack(push,8) /* is necessary for COM interfaces */
#endif

_CAMLIDL_EXTERN_C void f(void);

struct ITest;
#ifdef __cplusplus
struct ITest {
virtual HRESULT STDMETHODCALLTYPE QueryInterface(IID *, void **);
virtual ULONG STDMETHODCALLTYPE AddRef();
virtual ULONG STDMETHODCALLTYPE Release();
virtual void STDMETHODCALLTYPE method();
};
#else
struct ITestVtbl {
DECLARE_VTBL_PADDING
HRESULT (STDMETHODCALLTYPE *QueryInterface)(struct ITest *, IID *, void **);
ULONG (STDMETHODCALLTYPE *AddRef)(struct ITest *);
ULONG (STDMETHODCALLTYPE *Release)(struct ITest *);
void (STDMETHODCALLTYPE *method)(struct ITest * self);
};
struct ITest {
struct ITestVtbl * lpVtbl;
};
#endif
_CAMLIDL_EXTERN_C IID IID_ITest;

#ifdef _WIN32
#pragma pack(pop)
#endif

#endif /* !_CAMLIDL_CPLUSPLUS_H */
[---cut---]