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

[Frank Goenninger]

Hi Duncan,

glad you're jumping in on this !

Am 14.11.2009 um 21:18 schrieb Duncan Grisby:

> omniidl thinks your IDL file is empty. I don't know why. The fact that
> omniidl isn't seeing your IDL explains why it doesn't complain about  
> the
> errors in the IDL.
>
> The empty generated code claims to come from omniORB 4.2 (the current
> development branch), yet you say you are using omniORB 4.1.4. What
> exactly are you doing, and how?  Give step-by-step details of exactly
> what you have done.

I have to correct myself here: It actually is 4.2, the development  
branch.

> How does the way you are running omniidl differ from the way omniidl  
> is
> run when the echo example is compiled?  If the echo example works,
> omniidl is clearly working fine.

Let's see:

1. I cloned the Echo example in my own little omniorb-test project:

$ more omniorb-test.idl
interface Echo
   {
     string echoString(in string mesg);
   };

$ omniidl -bcxx omniorb-test.idl

produces fully intact files omniorb-test.hh and omniorb-testSK.cc  
which I have successfully used to play with various aspects of POA and  
Name Service.

I then went on to create my real project. I started with an new  
directory "~/flexio/idl" and put the IDL file as given here:

-X-X-X-

#pragma prefix "flexio.goenninger.net"

module FlexIO
{
   interface DeviceSelection;
   interface LowLevelIO;

   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 );
   };
};

-X-X-X-

Then:

$ cd ~/gnc/flexio/idl

$ ll
total 8
-rw-r--r--@ 1 frgo  staff  2660 14 Nov 21:35 flexio.idl

Making sure I am using the right omniidl:

$ type omniidl
omniidl is hashed (/opt/orb/bin/omniidl)

Ok, this is where I installed it. So, let's call it for code  
generation for flexio.idl:

$ omniidl -bcxx flexio.idl

gives:

$ ll
total 24
-rw-r--r--  1 frgo  staff  1552 14 Nov 21:41 flexio.hh
-rw-r--r--@ 1 frgo  staff  2660 14 Nov 21:35 flexio.idl
-rw-r--r--  1 frgo  staff   347 14 Nov 21:41 flexioSK.cc

with flexio.hh and flexioSK.cc being the "empty" files.

I then went on to see what omniidl sees as preprocessing output:

$ omniidl -E -bcxx flexio.idl

gives:

# 1 "flexio.idl"
??#pragma prefix "flexio.goenninger.net"

module FlexIO
{
   interface DeviceSelection;
   interface LowLevelIO;

   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 );
   };
};

The "??" appears whatever I have in the first line. Comparison with  
the omniorb-test.idl file:

$ omniidl -E -bcxx omniorb-test.idl

# 1 "omniorb-test.idl"
interface Echo
   {
     string echoString(in string mesg);
   };

Aha! No "??" at the beginning. Strange! Now: Let's see the file  
contents at the byte level:

$ od -c omniorb-test.idl

0000000    i   n   t   e   r   f   a   c   e       E   c   h   o      \n

Good. Now flexio.idl:

$ od -c flexio.idl

0000000  377 376   #  \0   p  \0   r  \0   a  \0   g  \0   m  \0   a  \0

Aha! So: 2-byte coded file versus 1-byte coded file. Converting to 1- 
byte coded file and re-issueing omniidl gives:

$ omniidl -bcxx flexio.idl
flexio.idl:19: Declaration of struct 'FlexIOServerInfo' clashes with  
earlier declaration of struct 'FlexIOServerInfo'
flexio.idl:14:  (struct 'FlexIOServerInfo' declared here)
flexio.idl:19: Syntax error in struct definition
flexio.idl:38: Declaration of struct 'FlexIOInfo' clashes with earlier  
declaration of struct 'FlexIOInfo'
flexio.idl:33:  (struct 'FlexIOInfo' declared here)
flexio.idl:38: Syntax error in struct definition
omniidl: 4 errors.

I have a valid output - this being errors, well ;-) Mystery solved.  
Still: I think an error output and a hint in the docs would be  
helpful. Note: I generated the file in Mac OS X's Xcode program, the  
standard IDE on OS X. I have set the encoding default to UTF-8 which  
caused this problem, not knowing omniidl wouldn't recognize UTF-8  
encoded files. It may be in the docs somewhere (I didn't check) but it  
sure would help if there was a warning or error message when running  
omniidl and it nit generating any contents.

Thanks for putting me on the right track!

Cheers
   Frank