openDAQ
Open data acquisition platform
Public Member Functions | List of all members
IFunction Struct Referenceabstract
Core Types » Function Types » Function

Holds a callback function. More...

+ Inheritance diagram for IFunction:
+ Collaboration diagram for IFunction:

Detailed Description

Holds a callback function.

Represents a callable object. The openDAQ SDK uses this interface when it needs to make a call back to the client.

Although the implementation of this interface is provided by openDAQ, C++ and other bindings provide their implementation which allows passing function as a lambda functions and other constructs.

Available factories:

// Creates a new Function object. Throws exception if not successful.
IFunction* Function_Create(FuncCall value)
// Creates a new Function object. Returns error code if not successful.
ErrCode createFunction(IFuncObject** obj, FuncCall value)
ErrCode
BEGIN_NAMESPACE_OPENDAQ typedef uint32_t ErrCode
Definition: common.h:60
FuncCall
ErrCode(* FuncCall)(IBaseObject *, IBaseObject **)
Function pointer to callback.
Definition: function.h:30
IFunction
Holds a callback function.
Definition: function.h:52

Public Member Functions

virtual ErrCode INTERFACE_FUNC call (IBaseObject *params, IBaseObject **result)=0
 Calls the stored callback. More...
 
- Public Member Functions inherited from IBaseObject
virtual ErrCode INTERFACE_FUNC borrowInterface (const IntfID &intfID, void **obj) const =0
 Returns another interface which is supported by the object without incrementing the reference count. More...
 
virtual ErrCode INTERFACE_FUNC dispose ()=0
 Disposes all references held by the object. More...
 
virtual ErrCode INTERFACE_FUNC getHashCode (SizeT *hashCode)=0
 Returns hash code of the object. More...
 
virtual ErrCode INTERFACE_FUNC equals (IBaseObject *other, Bool *equal) const =0
 Compares object to another object for equality. More...
 
virtual ErrCode INTERFACE_FUNC toString (CharPtr *str)=0
 Returns a string representation of the object. More...
 
- Public Member Functions inherited from IUnknown
virtual ErrCode INTERFACE_FUNC queryInterface (const IntfID &intfID, void **obj)=0
 Returns another interface which is supported by the object and increments the reference count. More...
 
virtual int INTERFACE_FUNC addRef ()=0
 Increments the reference count for an interface on an object. More...
 
virtual int INTERFACE_FUNC releaseRef ()=0
 Decrements the reference count for an interface on an object. More...
 

Member Function Documentation

◆ call()

virtual ErrCode INTERFACE_FUNC call ( IBaseObject *  params,
IBaseObject **  result 
)
pure virtual

Calls the stored callback.

Parameters
paramsParameters passed to the callback.
[out]resultReturn value of the callback.

If the callback expects no parameters, the params parameter has to be null. If it expects a single parameter, pass any openDAQ object as the params parameter. If it expects multiple parameters, pass an IList<IBaseObject> as the params parameter.