libSBML C++ API  5.20.2
MultiCompartmentPlugin Class Reference
Inheritance diagram for MultiCompartmentPlugin:
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Detailed Description

multi Extension of Compartment for the "multi" package.

The MultiCompartmentPlugin object is used to extend the standard SBML Compartment base object with an optional "compartmentType" attribute, a required "isType" Boolean attribute, and a child ListOfCompartmentReferences. The "isType" attribute flags whether this Compartment should be treated as a standard SBML Compartment (if false), or as a more generic rule-based "type" of Compartment (if true). A compartment "type" is a template (in the sense of prototype) for all Compartment objects referencing it (via "compartmentType" attributes). A Species object directly referencing a compartment type is not a "fully defined" species, but rather a "template" species. If the value of the "isType" attribute is false, the Compartment object is a "not-a-type" compartment, and it is similar to a SBML core Compartment except it can reference a compartment type and can have a ListOfCompartmentReferences child. Each child CompartmentReference in the ListOfCompartmentReferences defines a subcompartment of the parent Compartment. The "compartmentType" attribute identifies this Compartment as the CompartmentType defined elsewhere in the Model. If the "compartmentType" attribute is set, the "isType" attribute must be true.

Public Member Functions

int addCompartmentReference (const CompartmentReference *compartmentReference)
 Adds a copy of the given CompartmentReference object to the ListOfCompartmentReferences. More...
 
virtual MultiCompartmentPluginclone () const
 Creates and returns a deep copy of this MultiCompartmentPlugin object. More...
 
CompartmentReferencecreateCompartmentReference ()
 Creates a new CompartmentReference object and adds it to the ListOfCompartmentReferences. More...
 
virtual ListgetAllElements (ElementFilter *filter=NULL)
 Returns a List of all child SBase objects, including those nested to an arbitary depth. More...
 
CompartmentReferencegetCompartmentReference (const std::string &sid)
 Returns the CompartmentReference with the given identifier sid. More...
 
const CompartmentReferencegetCompartmentReference (const std::string &sid) const
 Returns the CompartmentReference with the given identifier sid. More...
 
CompartmentReferencegetCompartmentReference (unsigned int n)
 Returns the nth CompartmentReference object from the ListOfCompartmentReferences. More...
 
const CompartmentReferencegetCompartmentReference (unsigned int n) const
 Returns the nth CompartmentReference object from the ListOfCompartmentReferences. More...
 
virtual const std::string & getCompartmentType () const
 Returns the value of the "compartmentType" attribute of this compartment. More...
 
virtual SBasegetElementByMetaId (const std::string &metaid)
 Return the first child object found with a given meta identifier. More...
 
virtual SBasegetElementBySId (const std::string &id)
 Return the first child object found with a given identifier. More...
 
const std::string & getElementNamespace () const
 Returns the namespace URI of the package to which this plugin object belongs. More...
 
virtual bool getIsType () const
 Returns the value of the "isType" attribute. More...
 
unsigned int getLevel () const
 Returns the SBML Level of the package extension of this plugin object. More...
 
ListOfCompartmentReferencesgetListOfCompartmentReferences ()
 Returns the ListOfCompartmentReferences object. More...
 
const ListOfCompartmentReferencesgetListOfCompartmentReferences () const
 Returns the ListOfCompartmentReferences object. More...
 
unsigned int getNumCompartmentReferences () const
 Returns the number of CompartmentReference objects in the ListOfCompartmentReferences. More...
 
const std::string & getPackageName () const
 Returns the short-form name of the package to which this plugin object belongs. More...
 
unsigned int getPackageVersion () const
 Returns the package version of the package extension of this plugin object. More...
 
SBasegetParentSBMLObject ()
 Returns the parent object to which this plugin object is connected. More...
 
const SBasegetParentSBMLObject () const
 Returns the parent object to which this plugin object is connected. More...
 
const std::string & getPrefix () const
 Returns the XML namespace prefix of the package to which this plugin object belongs. More...
 
SBMLDocumentgetSBMLDocument ()
 Returns the SBMLDocument object containing this object instance. More...
 
const SBMLDocumentgetSBMLDocument () const
 Returns the SBMLDocument object containing this object instance. More...
 
std::string getURI () const
 Returns the XML namespace URI for the package to which this object belongs. More...
 
unsigned int getVersion () const
 Returns the Version within the SBML Level of the package extension of this plugin object. More...
 
virtual bool hasRequiredElements () const
 Returns true if this object has all the required elements. More...
 
virtual bool isSetCompartmentType () const
 Returns true if this compartment's "compartmentType" attribute has been set. More...
 
virtual bool isSetIsType () const
 Returns true if this compartment's "isType" attribute has been set. More...
 
virtual bool isValidTypeForList (SBase *item) const
 
 MultiCompartmentPlugin (const MultiCompartmentPlugin &orig)
 Copy constructor for MultiCompartmentPlugin. More...
 
 MultiCompartmentPlugin (const std::string &uri, const std::string &prefix, MultiPkgNamespaces *multins)
 Creates a new MultiCompartmentPlugin object. More...
 
MultiCompartmentPluginoperator= (const MultiCompartmentPlugin &rhs)
 Assignment operator for MultiCompartmentPlugin. More...
 
CompartmentReferenceremoveCompartmentReference (const std::string &sid)
 Removes the CompartmentReference object with the given identifier from the ListOfCompartmentReferences. More...
 
CompartmentReferenceremoveCompartmentReference (unsigned int n)
 Removes the nth CompartmentReference object from the ListOfCompartmentReferences. More...
 
virtual void renameMetaIdRefs (const std::string &oldid, const std::string &newid)
 
virtual void renameSIdRefs (const std::string &oldid, const std::string &newid)
 
virtual void renameUnitSIdRefs (const std::string &oldid, const std::string &newid)
 
virtual int setCompartmentType (const std::string &compartmentType)
 Sets the value of the "compartmentType" attribute on this compartment. More...
 
int setElementNamespace (const std::string &uri)
 Sets the XML namespace to which this object belongs. More...
 
virtual int setIsType (bool isType)
 Sets the value of the "isType" attribute. More...
 
virtual int unsetCompartmentType ()
 Unsets the value of the "compartmentType" attribute. More...
 
virtual int unsetIsType ()
 Unsets the value of the "isType" attribute. More...
 
virtual ~MultiCompartmentPlugin ()
 Destructor for MultiCompartmentPlugin. More...
 

Constructor & Destructor Documentation

◆ MultiCompartmentPlugin() [1/2]

MultiCompartmentPlugin::MultiCompartmentPlugin ( const std::string &  uri,
const std::string &  prefix,
MultiPkgNamespaces multins 
)

Creates a new MultiCompartmentPlugin object.

In the XML representation of an SBML document, XML namespaces are used to identify the origin of each XML construct used. XML namespaces are identified by their unique resource identifiers (URIs). The core SBML specifications stipulate the namespaces that must be used for core SBML constructs; for example, all XML elements that belong to SBML Level 3 Version 1 Core must be placed in the XML namespace identified by the URI "http://www.sbml.org/sbml/level3/version1/core". Individual SBML Level 3 packages define their own XML namespaces; for example, all elements belonging to the SBML Level 3 Layout Version 1 package must be placed in the XML namespace "http://www.sbml.org/sbml/level3/version1/layout/version1/".
The SBMLNamespaces object encapsulates SBML Level/Version/namespaces information. It is used to communicate the SBML Level, Version, and (in Level 3) packages used in addition to SBML Level 3 Core. A common approach to using libSBML's SBMLNamespaces facilities is to create an SBMLNamespaces object somewhere in a program once, then hand that object as needed to object constructors that accept SBMLNamespaces as arguments.
Parameters
urithe URI of the SBML Level 3 package implemented by this libSBML package extension.
prefixthe XML namespace prefix being used for the package.
multinsthe namespaces object for the package.

◆ MultiCompartmentPlugin() [2/2]

MultiCompartmentPlugin::MultiCompartmentPlugin ( const MultiCompartmentPlugin orig)

Copy constructor for MultiCompartmentPlugin.

Parameters
origthe MultiCompartmentPlugin instance to copy.

◆ ~MultiCompartmentPlugin()

MultiCompartmentPlugin::~MultiCompartmentPlugin ( )
virtual

Destructor for MultiCompartmentPlugin.

Member Function Documentation

◆ addCompartmentReference()

int MultiCompartmentPlugin::addCompartmentReference ( const CompartmentReference compartmentReference)

Adds a copy of the given CompartmentReference object to the ListOfCompartmentReferences.

Parameters
compartmentReferencethe CompartmentReference object to add.
Returns
integer value indicating success/failure of the function. The value is drawn from the enumeration OperationReturnValues_t. The possible values returned by this function are:

◆ clone()

MultiCompartmentPlugin * MultiCompartmentPlugin::clone ( ) const
virtual

Creates and returns a deep copy of this MultiCompartmentPlugin object.

Returns
a (deep) copy of this MultiCompartmentPlugin object.

Reimplemented from SBasePlugin.

◆ createCompartmentReference()

CompartmentReference * MultiCompartmentPlugin::createCompartmentReference ( )

Creates a new CompartmentReference object and adds it to the ListOfCompartmentReferences.

Returns
the newly created CompartmentReference object.

◆ getAllElements()

List * MultiCompartmentPlugin::getAllElements ( ElementFilter filter = NULL)
virtual

Returns a List of all child SBase objects, including those nested to an arbitary depth.

Parameters
filtera pointer to an ElementFilter, which causes the function to return only elements that match a particular set of constraints. If NULL (the default), the function will return all child objects.
Returns
a List of pointers to all child objects.

Reimplemented from SBasePlugin.

◆ getCompartmentReference() [1/4]

CompartmentReference * MultiCompartmentPlugin::getCompartmentReference ( const std::string &  sid)

Returns the CompartmentReference with the given identifier sid.

Parameters
sidthe identifier of the CompartmentReference object to get from the ListOfCompartmentReferences.
Returns
the CompartmentReference object with the given identifier in the ListOfCompartmentReferences, or NULL if no such CompartmentReference exists.

◆ getCompartmentReference() [2/4]

const CompartmentReference * MultiCompartmentPlugin::getCompartmentReference ( const std::string &  sid) const

Returns the CompartmentReference with the given identifier sid.

Parameters
sidthe identifier of the CompartmentReference object to get from the ListOfCompartmentReferences.
Returns
the CompartmentReference object with the given identifier in the ListOfCompartmentReferences, or NULL if no such CompartmentReference exists.

◆ getCompartmentReference() [3/4]

CompartmentReference * MultiCompartmentPlugin::getCompartmentReference ( unsigned int  n)

Returns the nth CompartmentReference object from the ListOfCompartmentReferences.

Parameters
nthe index number of the CompartmentReference to get.
Returns
the nth CompartmentReference, or NULL if the index n is out of range.

◆ getCompartmentReference() [4/4]

const CompartmentReference * MultiCompartmentPlugin::getCompartmentReference ( unsigned int  n) const

Returns the nth CompartmentReference object from the ListOfCompartmentReferences.

Parameters
nthe index number of the CompartmentReference to get.
Returns
the nth CompartmentReference, or NULL if the index n is out of range.

◆ getCompartmentType()

const std::string & MultiCompartmentPlugin::getCompartmentType ( ) const
virtual

Returns the value of the "compartmentType" attribute of this compartment.

Returns
the "compartmentType" attribute value.

◆ getElementByMetaId()

SBase * SBasePlugin::getElementByMetaId ( const std::string &  metaid)
virtualinherited

Return the first child object found with a given meta identifier.

This method searches all the subobjects under this one, compares their meta identifiers to metaid, and returns the first one that machines.

Parameters
metaidstring, the metaid of the object to find.
Returns
pointer to the first object found with the given metaid.

Reimplemented in SpatialParameterPlugin, SpatialModelPlugin, SpatialCompartmentPlugin, QualModelPlugin, GroupsModelPlugin, FbcSBasePlugin, FbcModelPlugin, DistribSBasePlugin, CompSBMLDocumentPlugin, CompSBasePlugin, and CompModelPlugin.

◆ getElementBySId()

SBase * SBasePlugin::getElementBySId ( const std::string &  id)
virtualinherited

Return the first child object found with a given identifier.

This method searches all the subobjects under this one, compares their identifiers to id, and returns the first one that machines. It uses SBasePlugin::getAllElements(ElementFilter* filter) to get the list of identifiers, so the order in which identifiers are searched is the order in which they appear in the results returned by that method.

Normally, SId type identifier values are unique across a model in SBML. However, in some circumstances they may not be, such as if a model is invalid because of multiple objects having the same identifier.

Parameters
idstring representing the identifier of the object to find.
Returns
pointer to the first object with the given id.

Reimplemented in SpatialParameterPlugin, SpatialModelPlugin, SpatialCompartmentPlugin, QualModelPlugin, GroupsModelPlugin, FbcSBasePlugin, FbcModelPlugin, DistribSBasePlugin, CompSBMLDocumentPlugin, CompSBasePlugin, and CompModelPlugin.

◆ getElementNamespace()

const std::string & SBasePlugin::getElementNamespace ( ) const
inherited

Returns the namespace URI of the package to which this plugin object belongs.

Returns
the XML namespace URI of the SBML Level 3 package implemented by this libSBML package extension.

◆ getIsType()

bool MultiCompartmentPlugin::getIsType ( ) const
virtual

Returns the value of the "isType" attribute.

Returns
the value of the "isType" attribute.

◆ getLevel()

unsigned int SBasePlugin::getLevel ( ) const
inherited

Returns the SBML Level of the package extension of this plugin object.

Returns
the SBML Level.
See also
getVersion()

◆ getListOfCompartmentReferences() [1/2]

ListOfCompartmentReferences * MultiCompartmentPlugin::getListOfCompartmentReferences ( )

Returns the ListOfCompartmentReferences object.

Returns
the ListOfCompartmentReferences object within this "multi" Compartment.

◆ getListOfCompartmentReferences() [2/2]

const ListOfCompartmentReferences * MultiCompartmentPlugin::getListOfCompartmentReferences ( ) const

Returns the ListOfCompartmentReferences object.

Returns
the ListOfCompartmentReferences object within this "multi" Compartment object.

◆ getNumCompartmentReferences()

unsigned int MultiCompartmentPlugin::getNumCompartmentReferences ( ) const

Returns the number of CompartmentReference objects in the ListOfCompartmentReferences.

Returns
the number of CompartmentReference objects.

◆ getPackageName()

const std::string & SBasePlugin::getPackageName ( ) const
inherited

Returns the short-form name of the package to which this plugin object belongs.

Returns
the short-form package name (or nickname) of the SBML package implemented by this package extension.

◆ getPackageVersion()

unsigned int SBasePlugin::getPackageVersion ( ) const
inherited

Returns the package version of the package extension of this plugin object.

Returns
the package version of the package extension of this plugin object.
See also
getLevel()
getVersion()

◆ getParentSBMLObject() [1/2]

SBase * SBasePlugin::getParentSBMLObject ( )
inherited

Returns the parent object to which this plugin object is connected.

Returns
the parent object of this object.

◆ getParentSBMLObject() [2/2]

const SBase * SBasePlugin::getParentSBMLObject ( ) const
inherited

Returns the parent object to which this plugin object is connected.

Returns
the parent object of this object.

◆ getPrefix()

const std::string & SBasePlugin::getPrefix ( ) const
inherited

Returns the XML namespace prefix of the package to which this plugin object belongs.

Returns
the XML namespace prefix of the SBML Level 3 package implemented by this libSBML package extension.

◆ getSBMLDocument() [1/2]

SBMLDocument * SBasePlugin::getSBMLDocument ( )
inherited

Returns the SBMLDocument object containing this object instance.

LibSBML uses the class SBMLDocument as a top-level container for storing SBML content and data associated with it (such as warnings and error messages). An SBML model in libSBML is contained inside an SBMLDocument object. SBMLDocument corresponds roughly to the class SBML defined in the SBML Level 3 and Level 2 specifications, but it does not have a direct correspondence in SBML Level 1. (But, it is created by libSBML no matter whether the model is Level 1, Level 2 or Level 3.)

This method allows the caller to obtain the SBMLDocument for the current object.

Returns
the parent SBMLDocument object of this plugin object.
See also
getParentSBMLObject()

◆ getSBMLDocument() [2/2]

const SBMLDocument * SBasePlugin::getSBMLDocument ( ) const
inherited

Returns the SBMLDocument object containing this object instance.

LibSBML uses the class SBMLDocument as a top-level container for storing SBML content and data associated with it (such as warnings and error messages). An SBML model in libSBML is contained inside an SBMLDocument object. SBMLDocument corresponds roughly to the class SBML defined in the SBML Level 3 and Level 2 specifications, but it does not have a direct correspondence in SBML Level 1. (But, it is created by libSBML no matter whether the model is Level 1, Level 2 or Level 3.)

This method allows the caller to obtain the SBMLDocument for the current object.

Returns
the parent SBMLDocument object of this plugin object.
See also
getParentSBMLObject()

◆ getURI()

std::string SBasePlugin::getURI ( ) const
inherited

Returns the XML namespace URI for the package to which this object belongs.

In the XML representation of an SBML document, XML namespaces are used to identify the origin of each XML construct used. XML namespaces are identified by their unique resource identifiers (URIs). The core SBML specifications stipulate the namespaces that must be used for core SBML constructs; for example, all XML elements that belong to SBML Level 3 Version 1 Core must be placed in the XML namespace identified by the URI "http://www.sbml.org/sbml/level3/version1/core". Individual SBML Level 3 packages define their own XML namespaces; for example, all elements belonging to the SBML Level 3 Layout Version 1 package must be placed in the XML namespace "http://www.sbml.org/sbml/level3/version1/layout/version1/".

This method first looks into the SBMLNamespaces object possessed by the parent SBMLDocument object of the current object. If this cannot be found, this method returns the result of getElementNamespace().

Returns
a string, the URI of the XML namespace to which this object belongs.
See also
getPackageName()
getElementNamespace()
getSBMLDocument()

◆ getVersion()

unsigned int SBasePlugin::getVersion ( ) const
inherited

Returns the Version within the SBML Level of the package extension of this plugin object.

Returns
the SBML Version.
See also
getLevel()

◆ hasRequiredElements()

bool MultiCompartmentPlugin::hasRequiredElements ( ) const
virtual

Returns true if this object has all the required elements.

Returns
true if this object has all the elements required by the package specification; otherwise, false will be returned.

◆ isSetCompartmentType()

bool MultiCompartmentPlugin::isSetCompartmentType ( ) const
virtual

Returns true if this compartment's "compartmentType" attribute has been set.

Returns
true if the "compartmentType" attribute has been set; otherwise, false is returned.

◆ isSetIsType()

bool MultiCompartmentPlugin::isSetIsType ( ) const
virtual

Returns true if this compartment's "isType" attribute has been set.

Returns
true if the "isType" attribute has been set; otherwise, false is returned.

◆ isValidTypeForList()

virtual bool SBasePlugin::isValidTypeForList ( SBase item) const
virtualinherited

◆ operator=()

MultiCompartmentPlugin & MultiCompartmentPlugin::operator= ( const MultiCompartmentPlugin rhs)

Assignment operator for MultiCompartmentPlugin.

Parameters
rhsthe object whose values are used as the basis of the assignment

◆ removeCompartmentReference() [1/2]

CompartmentReference * MultiCompartmentPlugin::removeCompartmentReference ( const std::string &  sid)

Removes the CompartmentReference object with the given identifier from the ListOfCompartmentReferences.

Parameters
sidthe id of the CompartmentReference to remove.
Returns
the CompartmentReference object removed, or NULL if no such CompartmentReference exists. Note that the caller owns the returned object and is responsible for deleting it.

◆ removeCompartmentReference() [2/2]

CompartmentReference * MultiCompartmentPlugin::removeCompartmentReference ( unsigned int  n)

Removes the nth CompartmentReference object from the ListOfCompartmentReferences.

Parameters
nthe index of the CompartmentReference to remove.
Returns
the CompartmentReference object removed, or NULL if the given index n is out of range. Note that the caller owns the returned object and is responsible for deleting it.

◆ renameMetaIdRefs()

virtual void SBasePlugin::renameMetaIdRefs ( const std::string &  oldid,
const std::string &  newid 
)
virtualinherited

Replaces all uses of a given meta identifier attribute value with another value.
In SBML, object "meta" identifiers are of the XML data type ID; the SBML object attribute itself is typically named metaid. All attributes that hold values referring to values of type ID are of the XML data type IDREF. They are also sometimes informally referred to as "metaid refs", in analogy to the SBML-defined type SIdRef.

This method works by looking at all meta-identifier attribute values, comparing the identifiers to the value of oldid. If any matches are found, the matching identifiers are replaced with newid. The method does not descend into child elements.

Parameters
oldidthe old identifier.
newidthe new identifier.

◆ renameSIdRefs()

virtual void SBasePlugin::renameSIdRefs ( const std::string &  oldid,
const std::string &  newid 
)
virtualinherited

Replaces all uses of a given SIdRef type attribute value with another value.

In SBML, object identifiers are of a data type called SId. In SBML Level 3, an explicit data type called SIdRef was introduced for attribute values that refer to SId values; in previous Levels of SBML, this data type did not exist and attributes were simply described to as "referring to an identifier", but the effective data type was the same as SIdRef in Level 3. These and other methods of libSBML refer to the type SIdRef for all Levels of SBML, even if the corresponding SBML specification did not explicitly name the data type.

This method works by looking at all attributes and (if appropriate) mathematical formulas in MathML content, comparing the referenced identifiers to the value of oldid. If any matches are found, the matching values are replaced with newid. The method does not descend into child elements.

Parameters
oldidthe old identifier.
newidthe new identifier.

Reimplemented in FbcReactionPlugin.

◆ renameUnitSIdRefs()

virtual void SBasePlugin::renameUnitSIdRefs ( const std::string &  oldid,
const std::string &  newid 
)
virtualinherited

Replaces all uses of a given UnitSIdRef type attribute value with another value.
In SBML, unit definitions have identifiers of type UnitSId. In SBML Level 3, an explicit data type called UnitSIdRef was introduced for attribute values that refer to UnitSId values; in previous Levels of SBML, this data type did not exist and attributes were simply described to as "referring to a unit identifier", but the effective data type was the same as UnitSIdRef in Level 3. These and other methods of libSBML refer to the type UnitSIdRef for all Levels of SBML, even if the corresponding SBML specification did not explicitly name the data type.

This method works by looking at all unit identifier attribute values (including, if appropriate, inside mathematical formulas), comparing the referenced unit identifiers to the value of oldid. If any matches are found, the matching values are replaced with newid. The method does not descend into child elements.

Parameters
oldidthe old identifier.
newidthe new identifier.

◆ setCompartmentType()

int MultiCompartmentPlugin::setCompartmentType ( const std::string &  compartmentType)
virtual

Sets the value of the "compartmentType" attribute on this compartment.

Parameters
compartmentTypethe new value for the attribute.
Returns
integer value indicating success/failure of the function. The value is drawn from the enumeration OperationReturnValues_t. The possible values returned by this function are:

◆ setElementNamespace()

int SBasePlugin::setElementNamespace ( const std::string &  uri)
inherited

Sets the XML namespace to which this object belongs.

In the XML representation of an SBML document, XML namespaces are used to identify the origin of each XML construct used. XML namespaces are identified by their unique resource identifiers (URIs). The core SBML specifications stipulate the namespaces that must be used for core SBML constructs; for example, all XML elements that belong to SBML Level 3 Version 1 Core must be placed in the XML namespace identified by the URI "http://www.sbml.org/sbml/level3/version1/core". Individual SBML Level 3 packages define their own XML namespaces; for example, all elements belonging to the SBML Level 3 Layout Version 1 package must be placed in the XML namespace "http://www.sbml.org/sbml/level3/version1/layout/version1/".
Parameters
urithe URI to assign to this object.
Returns
integer value indicating success/failure of the function. The value is drawn from the enumeration OperationReturnValues_t. This particular function only does one thing irrespective of user input or object state, and thus will only return a single value:
See also
getElementNamespace()
Examples
convertLayout.cpp.

◆ setIsType()

int MultiCompartmentPlugin::setIsType ( bool  isType)
virtual

Sets the value of the "isType" attribute.

Parameters
isTypethe new value of the attribute.
Returns
integer value indicating success/failure of the function. The value is drawn from the enumeration OperationReturnValues_t. The possible values returned by this function are:

◆ unsetCompartmentType()

int MultiCompartmentPlugin::unsetCompartmentType ( )
virtual

Unsets the value of the "compartmentType" attribute.

Returns
integer value indicating success/failure of the function. The value is drawn from the enumeration OperationReturnValues_t. The possible values returned by this function are:

◆ unsetIsType()

int MultiCompartmentPlugin::unsetIsType ( )
virtual

Unsets the value of the "isType" attribute.

Returns
integer value indicating success/failure of the function. The value is drawn from the enumeration OperationReturnValues_t. The possible values returned by this function are: