pass-by-reference

问题 I have the parameters to send to a prepared statement in an array, I am using call_user_func_array and using it as such call_user_func_array(array($stmt, "bind_param"), array_merge(array($types), $params_fixed)) , where $types contains the types and $params_fixed contains the parameters. I ran it and got the error Warning: Parameter 2 to mysqli_stmt::bind_param() expected to be a reference, value given in ... , I searched for this error and an answer was to send the parameters by reference so

问题 I am currently struggling to get the following code to compile. First the header file containing a class with a method template: // ConfigurationContext.h class ConfigurationContext { public: template<typename T> T getValue(const std::string& name, T& default) const { ... } } Somewhere else I want to call this method like this: int value = context.getValue<int>("foo", 5); There I get the following error: error: no matching function for call to 'ConfigurationContext::getValue(const std::basic

问题 In order to get... void MinPriority::createArray(string targetVertex, Graph & graph) { vector <list <Graph::Edge> >& adjList = graph.get_adjList(); } to work I need to pass in Graph &graph by reference from another function: void Graph::MST_PRIM() { MinPriority priority; for(unsigned int i = 0; i != adjList.size(); i++) { priority.createArray(adjList[i].front().m_vertex, /*...*/); } } what would i put into /*...*/ to get createArray to work? Here is a rough example of what class Graph looks

问题 Is it possible in SAS to invoke a call to a macro using a macro variable whose value is the macro's name? Something like the following: %MACRO TEST (macroName, var1, var2, var3, var4, var5); %put LOG: %&macroName(&var1); %MEND; %TEST(testName,testVar1); In response to Richard's answer. I tried following your solution, but am still getting an "apparent invocation of macro YearMonthString not resolved" using the following code: %MACRO YearMonthString(nYear,nMonth); /* Builds a string in the

问题 In C++ when you want a function to be able to read from an object, but not modify it, you pass a const reference to the function. What is the equivalent way of doing this in php? I know objects in php5 are passed by reference by default, but for readability I think I will continue to use the ampersand before the variable name, like this: function foo(&$obj) { } 回答1: If you want to pass an object but not by reference you can clone the object beforehand. <?php function changeObject($obj) { $obj

问题 I am trying to connect a simulator to the MATLAB. The simulator program exposes a COM object interface. I have connected to the COM object by the following command and can perform most of it methods: h=actxserver(ProgID) But some of its methods need passing of a Variant* type as output. Here is the signature of one of the methods indicated by "invoke" method: ReadOutputImage=Variant(Pointer) ReadOutputImage(handle, int32, int32, `ImageDataTypeConstants, Variant(Pointer))` I have called this

问题 I have a ThreadPool class with an enqueue function: class ThreadPool { public: //(Code removed here) template <typename ... Args, typename Fun> JobId enqueue(Fun func, Args ... args); //(Code removed here) } And I use it on these non static member function loadStuff on class Object : class Object { //(Code removed here) void init(const PrepareData & prepareData); virtual bool loadStuff(const PrepareData & prepareData); //(Code removed here) } by calling in QObject::init : void QObject::init

问题 I'm trying to model a collection of objects in python (2). The collection should make a certain attribute (an integer, float or any immutable object) of the objects available via a list interface. (1) >>> print (collection.attrs) [1, 5, 3] >>> collection.attrs = [4, 2, 3] >>> print (object0.attr == 4) True I especially expect this list interface in the collection to allow for reassigning a single object's attribute, e.g. (2) >>> collection.attrs[2] = 8 >>> print (object2.attr == 8) True I am

问题 I was told a long time ago that in FORTRAN, everything is passed by value. Therefore I would need to do this (provided mySubroutine is suitably defined elsewhere): double precision :: myArray(2) myArray(1:2) = (/ 2.3d0, 1.5d0 /) CALL mySubroutine(myArray) However, I also found that the program compiles and runs as expected if I do this CALL mySubroutine((/ 2.3d0, 1.5d0 /)) without needing to define an intermediary array myArray . I thought that I was passing myArray into mySubroutine by

问题 This question already has an answer here : Python: How to share data between instances of different classes? (1 answer) Closed last year . I have been searching for the next answer but for sure I have been searching the wrong keywords. I used to develop with C++, passing pointers as references between objects. The case is, now I'm trying to build a program in Python where one instance of a class 'General' initializes different instances of a class 'Specific' with the same shared variable.