[omniORB] omniidl does not generate code - I'm mystified...

[Frank Goenninger]

Am 14.11.2009 um 16:25 schrieb Kevin Bailey:

> On Sat, Nov 14, 2009 at 10:14:30AM +0100, Frank Goenninger wrote:
>> Hello all,
>>
>> being a bloody beginner I am trying to get omniidl to generate code  
>> from
>> the following IDL file:
>>
>> -X-X-X-
>>
>> #ifndef __FLEXIO__
>> #define __FLEXIO__
>>
>> #pragma prefix "flexio.goenninger.net"
>>
>> module FlexIO
>> {
>>  typedef long            rc_t;
>>  typedef unsigned long   operation_t;
>>  typedef unsigned long   data_t;
>>  typedef unsigned long * data_ptr;
>>  typedef unsigned long   device_id_t;
>>
>>  interface LowLevelIO
>>  {
>>    rc_t select_device( in device_id_t device_id );
>>
>>    rc_t read( in  operation_t operation,
>>               in  data_t      data1,
>>               in  data_t      data2,
>>               out data_ptr    rtn );
>
> CORBA hasn't added pointers since I last used it, has it ?

No, it didn't, you're right. Yet I did not get any error output of  
omniidl. Stupid me, that's what I expected when I am using some  
illegal syntax in an IDL file.

> If not... How would CORBA implement them on platforms
> without pointers ? What good would a pointer be to a completely
> different process on a completely different host ? Different
> architecture perhaps.

Pointers are a mess of a concept to begin with, so better not  
implement them at all ;-)

>
> Instead, just use "out" parameters to implement returned data
> (as you seem to have done.)
>
> rc_t read(...
>          out data_t rtn);
>
> Or maybe an out array if it will return multiple words.

Brave as I am I changed my IDL file to the following:

-X-X-X-

#ifndef __FLEXIO__
#define __FLEXIO__

#pragma prefix "flexio.goenninger.net"

module FlexIO
{
   typedef long rc_t;

   typedef unsigned long device_id_t;
   typedef unsigned long bus_id_t;

   struct FlexIOServerInfo
   {
     string        ip_hostname;
     unsigned long tcp_port;
   };

   typedef struct FlexIOServerInfo flexioserverinfo_t;

   struct FlexIODeviceInfo
   {
     device_id_t  id;
     string       name;

     flexioserverinfo_t  server;
     bus_id_t            bus_id;
   };

   typedef sequence<FlexIODeviceInfo> flexiodeviceinfoseq_t;

   struct FlexIOInfo
   {
     long                  nr_devices;
     flexiodeviceinfoseq_t device_info_list;
   };

   typedef struct FlexIOInfo flexioinfo_t;

   interface DeviceSelection
   {
     rc_t get_flexio_info( out flexioinfo_t flex_io_info );
     rc_t select_device( in device_id_t device_id );
   };

   typedef unsigned long flexio_op_id_t;
   typedef unsigned long flexio_data_t;

   interface LowLevelIO
   {
     rc_t read( in  flexio_op_id_t operation,
                in  flexio_data_t  data1,
                in  flexio_data_t  data2,
                out flexio_data_t  return_value );

     rc_t write( in flexio_op_id_t operation,
                 in flexio_data_t data1,
                 in flexio_data_t data2 );
   };
};

#endif

-X-X-X-

... a bit more complex, but in line with what I can read in my Corba  
book "Pure Corba" (SAMS, Fintan Bolton). No pointers used. Still no  
output.

A call to omniidl to verify the IDL file returns no errors. Ok, I am  
just about to try some other ORB for this ... Or does OmniORB behave a  
bit different? In which way?

Mayday! Mayday! Lost engine 1 and 2, engine 3 on fire - engine 4  
almost without fuel ...

Frank