Went the subclassed exception route (at the expense of lots of extra

code and possibly extra maintenance). It will match the Python
interface and it's I guess what Stroustrup recommends.

example/C++/OO/eject.cpp

@@ -1,5 +1,5 @@
 /*
-  $Id: eject.cpp,v 1.3 2006/01/15 10:39:15 rocky Exp $
+  $Id: eject.cpp,v 1.4 2006/01/17 02:09:32 rocky Exp $
 
   Copyright (C) 2005 Rocky Bernstein <rocky@panix.com>
   
@@ -61,6 +61,10 @@ main(int argc, const char *argv[])
     device.ejectMedia(psz_drive);
     printf("CD in CD-ROM drive %s ejected.\n", psz_drive);
   }
+  catch ( CdioDevice::DriverOpUninit e ) {
+    printf("Can't Ejecting CD from CD-ROM drive: driver is not initialized.\n",
+	   psz_drive);
+  }
   catch ( CdioDevice::DriverOpException e ) {
     printf("Ejecting CD from CD-ROM drive %s operation error:\n\t%s.\n", 
 	   psz_drive, e.get_msg());

include/cdio++/cdio.hpp

@@ -1,5 +1,5 @@
 /* -*- C++ -*-
-    $Id: cdio.hpp,v 1.4 2006/01/15 10:39:15 rocky Exp $
+    $Id: cdio.hpp,v 1.5 2006/01/17 02:09:32 rocky Exp $
 
     Copyright (C) 2005, 2006 Rocky Bernstein <rocky@panix.com>
 
@@ -115,6 +115,7 @@ public:
   {
   public:
     driver_return_code_t driver_return_code;
+    DriverOpException( void ) { };
     DriverOpException( driver_return_code_t drc ) { 
       driver_return_code = drc; 
     };
@@ -126,6 +127,48 @@ public:
     };
   };
 
+  class DriverOpError: public DriverOpException
+  {
+  public:
+    DriverOpError(void) { driver_return_code = DRIVER_OP_ERROR; }
+  };
+
+  class DriverOpUnsupported: public DriverOpException 
+  { 
+  public:
+    DriverOpUnsupported(void) { driver_return_code = DRIVER_OP_UNSUPPORTED; }
+  };
+
+  class DriverOpUninit: public DriverOpException
+  {
+  public:
+    DriverOpUninit(void) { driver_return_code = DRIVER_OP_UNINIT; }
+  };
+
+  class DriverOpNotPermitted: public DriverOpException
+  {
+  public:
+    DriverOpNotPermitted(void) {driver_return_code = DRIVER_OP_NOT_PERMITTED;}
+  };
+
+  class DriverOpBadParameter: public DriverOpException
+  {
+  public:
+    DriverOpBadParameter(void) {driver_return_code = DRIVER_OP_BAD_PARAMETER;}
+  };
+
+  class DriverOpBadPointer: public DriverOpException
+  {
+  public:
+    DriverOpBadPointer(void) {driver_return_code = DRIVER_OP_BAD_POINTER;}
+  };
+
+  class DriverOpNoDriver: public DriverOpException
+  {
+  public:
+    DriverOpNoDriver(void) {driver_return_code = DRIVER_OP_NO_DRIVER;}
+  };
+
   // Other member functions  
 #include "device.hpp"
 #include "disc.hpp"
@@ -134,10 +177,28 @@ public:
 
 private:
   CdIo_t *p_cdio;
-  void throw_device_exception(driver_return_code_t drc) 
+  void possible_throw_device_exception(driver_return_code_t drc) 
   {
-    if (DRIVER_OP_SUCCESS == drc) return;
+    switch (drc) {
-    throw DriverOpException(drc);
+    case DRIVER_OP_SUCCESS:
+      return;
+    case DRIVER_OP_ERROR:
+      throw DriverOpError();
+    case DRIVER_OP_UNSUPPORTED:
+      throw DriverOpUnsupported();
+    case DRIVER_OP_UNINIT:
+      throw DriverOpUninit();
+    case DRIVER_OP_NOT_PERMITTED:
+      throw DriverOpNotPermitted();
+    case DRIVER_OP_BAD_PARAMETER:
+      throw DriverOpBadParameter();
+    case DRIVER_OP_BAD_POINTER:
+      throw DriverOpBadPointer();
+    case DRIVER_OP_NO_DRIVER:
+      throw DriverOpNoDriver();
+    default:
+      throw DriverOpException(drc);
+    }
   }
 };
 

include/cdio++/device.hpp

@@ -1,5 +1,5 @@
 /* -*- C++ -*-
-    $Id: device.hpp,v 1.2 2006/01/15 10:39:15 rocky Exp $
+    $Id: device.hpp,v 1.3 2006/01/17 02:09:32 rocky Exp $
 
     Copyright (C) 2005, 2006 Rocky Bernstein <rocky@panix.com>
 
@@ -47,7 +47,7 @@ close()
 void closeTray (const char *psz_drive, /*in/out*/ driver_id_t &driver_id) 
 {
   driver_return_code_t drc = cdio_close_tray (psz_drive, &driver_id);
-  throw_device_exception(drc);
+  possible_throw_device_exception(drc);
 }
 
 /*!
@@ -71,7 +71,7 @@ void
 ejectMedia () 
 {
   driver_return_code_t drc = cdio_eject_media(&p_cdio);
-  throw_device_exception(drc);
+  possible_throw_device_exception(drc);
 }
 
 /*!
@@ -83,7 +83,7 @@ void
 ejectMedia (const char *psz_drive) 
 {
   driver_return_code_t drc = cdio_eject_media_drive(psz_drive);
-  throw_device_exception(drc);
+  possible_throw_device_exception(drc);
 }
 
 /*! 
@@ -321,7 +321,7 @@ void
 getLastSession (/*out*/ lsn_t &i_last_session) 
 {
   driver_return_code_t drc = cdio_get_last_session(p_cdio, &i_last_session);
-  throw_device_exception(drc);
+  possible_throw_device_exception(drc);
 }
 
 /*! 
@@ -472,7 +472,7 @@ void
 setBlocksize ( int i_blocksize )
 {
   driver_return_code_t drc = cdio_set_blocksize ( p_cdio, i_blocksize );
-  throw_device_exception(drc);
+  possible_throw_device_exception(drc);
 }
 
 /*!
@@ -482,7 +482,7 @@ void
 setSpeed ( int i_speed ) 
 {
   driver_return_code_t drc = cdio_set_speed ( p_cdio, i_speed );
-  throw_device_exception(drc);
+  possible_throw_device_exception(drc);
 }
 
 /*!
@@ -495,6 +495,6 @@ void
 setArg (const char key[], const char value[]) 
 {
   driver_return_code_t drc = cdio_set_arg (p_cdio, key, value);
-  throw_device_exception(drc);
+  possible_throw_device_exception(drc);
 }