Provided by: libcoin60-doc_3.1.3-2_all bug

NAME

       SoType -

       The SoType class is the basis for the run-time type system in Coin.

       Many of the classes in the Coin library must have their type information registered before
       any instances are created (including, but not limited to: engines, nodes, fields, actions,
       nodekits and manipulators). The use of SoType to store this information provides lots of
       various functionality for working with class hierarchies, comparing class types,
       instantiating objects from classnames, etc etc.

SYNOPSIS

       #include <Inventor/SoType.h>

   Public Types
       typedef void *(* instantiationMethod )(void)

   Public Member Functions
       SbName getName (void) const
       const SoType getParent (void) const
       SbBool isDerivedFrom (const SoType type) const
       SbBool canCreateInstance (void) const
       void * createInstance (void) const
       uint16_t getData (void) const
       int16_t getKey (void) const
       SbBool operator== (const SoType type) const
       SbBool operator!= (const SoType type) const
       SbBool operator< (const SoType type) const
       SbBool operator<= (const SoType type) const
       SbBool operator>= (const SoType type) const
       SbBool operator> (const SoType type) const
       SbBool isBad (void) const
       void makeInternal (void)
       SbBool isInternal (void) const
       instantiationMethod getInstantiationMethod (void) const

   Static Public Member Functions
       static SoType fromName (const SbName name)
       static int getAllDerivedFrom (const SoType type, SoTypeList &list)
       static const SoType createType (const SoType parent, const SbName name, const
           instantiationMethod method=NULL, const uint16_t data=0)
       static const SoType overrideType (const SoType originalType, const instantiationMethod
           method=NULL)
       static SbBool removeType (const SbName &name)
       static void init (void)
       static SoType fromKey (uint16_t key)
       static SoType badType (void)
       static int getNumTypes (void)

Detailed Description

       The SoType class is the basis for the run-time type system in Coin.

       Many of the classes in the Coin library must have their type information registered before
       any instances are created (including, but not limited to: engines, nodes, fields, actions,
       nodekits and manipulators). The use of SoType to store this information provides lots of
       various functionality for working with class hierarchies, comparing class types,
       instantiating objects from classnames, etc etc.

       It is for instance possible to do things like this:

         void cleanLens(SoNode * anode)
         {
           assert(anode->getTypeId().isDerivedFrom(SoCamera::getClassTypeId()));

           if (anode->getTypeId() == SoPerspectiveCamera::getClassTypeId()) {
             // do something..
           }
           else if (anode->getTypeId() == SoOrthographicCamera::getClassTypeId()) {
             // do something..
           }
           else {
             SoDebugError::postWarning('cleanLens', 'Unknown camera type %s!0,
                                       anode->getTypeId().getName());
           }
         }

       A notable feature of the SoType class is that it is only 16 bits long and therefore should
       be passed around by value for efficiency reasons.

       One important note about the use of SoType to register class information: super classes
       must be registered before any of their derived classes are.

       See also Dynamic Loading of Extension Nodes for some additional SoType-related
       information.

Member Typedef Documentation

   SoType::instantiationMethod This is a convenience typedef for the function signature of a
       typed class' instantiation method. It is an extension on the original Inventor API. Mostly
       only useful for internal purposes.
       An instantation method will take no arguments and returns a void-pointer to a newly
       allocated and initialized object of the class type.

Member Function Documentation

   SoType SoType::fromName (const SbNamename) [static] This static function returns the SoType
       object associated with name name.
       Type objects for builtin types can be retreived by name both with and without the 'So'
       prefix. For dynamically loadable extension nodes, the name given to this function must
       match exactly.

       If no node type with the given name has been initialized, a dynamically loadable extension
       node with the given name is searched for. If one is found, it is loaded and initialized,
       and the SoType object for the newly initialized class type returned. If no module is
       found, or the initialization of the module fails, SoType::badType() is returned.

       Support for dynamically loadable extension nodes varies from platform to platform, and
       from compiler suite to compiler suite.

       So far code built with the following compilers are supported: GNU GCC v2, GNU GCC v3,
       Microsoft Visual C++ v6 (and probably v7, not tested), SGI MIPSPro v7.

       Extensions built with compilers that are known to be binary compatible with the above
       compilers are also supported, such as e.g. the Intel x86 compiler compatible with MSVC++.

       To support dynamic loading for other compilers, we need to know how the compiler mangles
       the 'static void classname::initClass(void)' symbol. If your compiler is not supported,
       tell us at coin-support@coin3d.org which it is and send us the output of a symbol-dump on
       the shared object. Typically you can do

         $ nm <Node>.so | grep initClass

       to find the relevant mangled symbol.

   SbName SoType::getName (void) const This method returns the name of the SoBase-derived class
       type the SoType object is configured for.
   const SoType SoType::getParent (void) const This method returns the SoType type for the parent
       class of the SoBase-derived class the SoType object is configured for.
   SbBool SoType::isDerivedFrom (const SoTypeparent) const This method returns TRUE if the given
       type is derived from (or is) the parent type, and FALSE otherwise.
   int SoType::getAllDerivedFrom (const SoTypetype, SoTypeList &list) [static] This method
       appends all the class types derived from type to list, and returns the number of types
       added to the list. Internal types are not included in the list, nor are they counted.
       type itself is also added to the list, as a type is seen as a derivation of its own type.

       NB: do not write code which depends in any way on the order of the elements returned in
       list.

       Here is a small, stand-alone example which shows how this method can be used for
       introspection, listing all subclasses of the SoBase superclass:

         #include <stdio.h>
         #include <Inventor/SoDB.h>
         #include <Inventor/lists/SoTypeList.h>

         static void
         list_subtypes(SoType t, unsigned int indent = 0)
         {
           SoTypeList tl;
           SoType::getAllDerivedFrom(t, tl);

           for (unsigned int i=0; i < indent; i++) { printf('  '); }
           printf('%s0, t.getName().getString());

           indent++;
           for (int j=0; j < tl.getLength(); j++) {
             if (tl[j].getParent() == t) { // only interested in direct descendents
               list_subtypes(tl[j], indent);
             }
           }
         }

         int
         main(void)
         {
           SoDB::init();

           list_subtypes(SoType::fromName('SoBase'));

           return 0;
         }

   SbBool SoType::canCreateInstance (void) const This method returns FALSE for abstract base
       classes, and TRUE for class types that can be instantiated.
   void * SoType::createInstance (void) const This method instantiates an object of the current
       type.
       For types that can not be instantiated, NULL is returned.

       Note that if the Coin library has been built as a DLL under Microsoft Windows and you use
       this method from application code, you must make sure that both the Coin DLL and the
       application executable is using the same instance of a C Run-Time (CRT) library.
       Otherwise, you will get memory heap corruption upon deallocating the returned instances,
       eventually leading to mysterious crashes.

       This is not harmful if you only call SoType::createInstance() on types for reference
       counted class-types, though. These include all nodes, engines, paths, nodekits, draggers
       and manipulators.

   uint16_t SoType::getData (void) const This method returns a type specific data variable.
   int16_t SoType::getKey (void) const [inline] This method returns the type's index in the
       internal typelist.
   SbBool SoType::operator== (const SoTypetype) const [inline] Check type equality.
   SbBool SoType::operator!= (const SoTypetype) const [inline] Check type inequality.
   SbBool SoType::operator< (const SoTypetype) const [inline] Comparison operator for sorting
       type data according to some internal criterion.
   SbBool SoType::operator<= (const SoTypetype) const [inline] Comparison operator for sorting
       type data according to some internal criterion.
   SbBool SoType::operator>= (const SoTypetype) const [inline] Comparison operator for sorting
       type data according to some internal criterion.
   SbBool SoType::operator> (const SoTypetype) const [inline] Comparison operator for sorting
       type data according to some internal criterion.
   const SoType SoType::createType (const SoTypeparent, const SbNamename, const
       instantiationMethodmethod = NULL, const uint16_tdata = 0) [static] This method creates and
       registers a new class type.
       Classes that do not inherit any other class should use SoType::badType() for the first
       argument. Abstract classes should use NULL for the method argument.

       The value passed in for the data parameter can be retrieved with SoType::getData().

   const SoType SoType::overrideType (const SoTypeoriginalType, const instantiationMethodmethod =
       NULL) [static] This method makes a new class's instantiation method override the
       instantiation method of an existing class.
       The new type should be a C++ subclass of the original class type, but this won't be
       checked though.

       If NULL is passed as the second argument, the type will be considered uninstantiable -- it
       does not revert the configuration to the default setting as one might think.

       Here's a complete code examples which shows how to fully override a built-in Coin node
       class, so that a) your application-specific extension class gets instantiated instead of
       the built-in class upon scenegraph import, and b) it gets written out properly upon
       export:

         #include <Inventor/SoDB.h>
         #include <Inventor/actions/SoWriteAction.h>
         #include <Inventor/errors/SoDebugError.h>
         #include <Inventor/nodes/SoSeparator.h>
         #include <Inventor/nodes/SoWWWInline.h>

         class MyWWWInline : public SoWWWInline {
           SO_NODE_HEADER(MyWWWInline);

         public:
           static void initClass(void);
           MyWWWInline(void);

         protected:
           virtual ~MyWWWInline();
           virtual SbBool readInstance(SoInput * in, unsigned short flags);
           virtual const char * getFileFormatName(void) const;
         };

         SO_NODE_SOURCE(MyWWWInline);

         MyWWWInline::MyWWWInline(void)
         {
           SO_NODE_CONSTRUCTOR(MyWWWInline);

           // Fool the library to believe this is an internal class, so it gets
           // written out in the same manner as the built-in classes, instead
           // of as en extension class. There are slight differences, which you
           // want to avoid when overriding a class like we do with MyWWWInline
           // vs SoWWWInline here.
           this->isBuiltIn = TRUE;
         }

         MyWWWInline::~MyWWWInline()
         {
         }

         void
         MyWWWInline::initClass(void)
         {
           SO_NODE_INIT_CLASS(MyWWWInline, SoWWWInline, 'SoWWWInline');

           // Override instantiation method, so we get MyWWWInline instead of
           // SoWWWInline instances upon scenegraph import.
           (void)SoType::overrideType(SoWWWInline::getClassTypeId(),
                                      MyWWWInline::createInstance);
         }

         // Override SoBase::getFileFormatName() to make node get written as
         // 'WWWInline' instead of 'MyWWWInline'.
         const char *
         MyWWWInline::getFileFormatName(void) const
         {
           return 'WWWInline';
         }

         SbBool
         MyWWWInline::readInstance(SoInput * in, unsigned short flags)
         {
           SoDebugError::postInfo('MyWWWInline::readInstance', 'hepp');
           return SoWWWInline::readInstance(in, flags);
         }

         int
         main(int argc, char ** argv)
         {
           SoDB::init();
           MyWWWInline::initClass();

           const char * ivscene =
             '#Inventor V2.1 ascii0
             'Separator {'
             '  WWWInline { }'
             '}';

           SoInput in;
           in.setBuffer((void *)ivscene, strlen(ivscene));
           SoSeparator * root = SoDB::readAll(&in);
           root->ref();

           SoOutput out;
           SoWriteAction wa(&out);
           wa.apply(root);
           root->unref();

           return 0;
         }

   SbBool SoType::removeType (const SbName &name) [static] This method removes class type from
       the class system. Returns FALSE if a type with the given name doesn't exist.
       Since:
           Coin 3.0

   void SoType::init (void) [static] This static method initializes the type system.
   SoType SoType::fromKey (uint16_tkey) [static] Find and return a type from the given key ID.
   SoType SoType::badType (void) [static] This method returns an illegal type, useful for
       returning errors.
       See also:
           SbBool SoType::isBad() const

   SbBool SoType::isBad (void) const [inline] This method returns TRUE if the SoType object
       represents an illegal class type.
   void SoType::makeInternal (void) This method turns the specific type into an internal type.
   SbBool SoType::isInternal (void) const This function returns TRUE if the type is an internal
       type.
   int SoType::getNumTypes (void) [static] This function returns the number of types registered
       in the run-time type system.
   SoType::instantiationMethod SoType::getInstantiationMethod (void) const Returns a pointer to
       the method used to instantiate objects of the given type.
       This function is an extension for Coin, and it is not available in the original SGI Open
       Inventor v2.1 API.

       Since:
           Coin 2.0

Author

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