If I declared that code in a header file I'd be able to call it with an int, float, double or whatever. But where does the actual code get instantiated? Is it effectively inlined?
What I'm wondering is if there'd ever be any scenario for putting such code in a DLL - e.g.
I just tried it and was slightly surprised to find it wouldn't compile. It compiles fine when actually building the DLL but when I try to build something else which uses that DLL I get compiler error C2491 (definition of dllimport function not allowed).
I guess that kinda makes sense if template functions are effectively inlined... or is there some other explanation....
I stumbled upon an unexpected difference between GCC and VisualStudio: Different overloaded functions are called in the following example:
// -------- can assume this is located in 'tool.h' file -------------- // Fwd declaration support foo( const int& ) gets called as expected by both compilers // void foo( const int& n );
template< typename T > void foo( const T& n ) {
[Code] ....
What happens: I expected that by calling bar(1) compiler will notice both versions of foo() and call the best match, in this case foo(const int&). That is not the case.
Note that overloaded foo(const int&) is below bar(). It seems that at that point GCC does not see overloaded version, and happily calls template version. Visual studio on the other hand has no problem finding them both.
If I introduce a forward declaration of foo( const int& ) before bar(), both compilers call that version correctly. Unfortunately, that is not a solution for my problem here.
Template version is part of a library while overloaded is part of the user code. Both would be located in different (header) files and I would not like to impose #include order to the users or to be dependant on it.
I'm trying to implement a simple template array class, but when i came into the operator< i actually have to use a template :
my code is something like :
template<typename _Type, std::size_t _Size> class array { public :
[Code] ......
but i am having an error of shadows template param 'class _Type' is it w/ the name conflict between the array template parameter and the function template parameter ?
where 'g()' returns an object of the element type. However, the compiler is claiming, no matter how I write a call to the overload, the original template is selected and/or the overload is invalid, depending on the various ways I attempt to write said overload.
i want to use a class to print data stored as vector or array with different data types. i also want the print function two take more than one vector or array or combination of both so that they can be written to file as two columns. so i wrote the following class:
right now it has only one member function for printing two vectors. later i'll add additional functions as required.
note: there has to be template functions inside the class i also want the object to be global so that i need not pass it as an argument to other calling functions
then i want to call this template function in another ordinary function written in a seperate cpp file
these function declarations are put in a header file. so i need know whether i should put the declaration of the template function in the header to use the function in different functions
i want to use a class to print data stored as vector or array with different data types.
i also want the print function two take more than one vector or array or combination of both so that they can be written to file as two columns.so i wrote the following class:
right now it has only one member function for printing two vectors. later i'll add additional functions as required.
note: there has to be template functions inside the class / i also want the object to be global so that i need not pass it as an argument to other calling functions
then i want to call this template function in another ordinary function written in a seperate cpp file these function declarations are put in a header file. so i need know whether i should put the declaration of the template function in the header to use the function in different functions.
You can check it here: [URL] The output is correct, but in my machine with C++11, MinGW 4.8 (64 bit in a 64bit-Windows8), the output is incorrect. Why?
If you want more specific info, the problem is that I use input, I think. I use std::getline(std::cin, some_string).
My question contains two projects that are under the same solution.
Project_1: I have created a dll where I use inside the project, OLE Db Template. In the project, I use this code.
class MyClass { public: LONG _value1; SHORT_value2; BEGIN_COLUMN_MAP(Accessor)
[Code] .....
Project_2: Is a project testing the Project_1.
- I want to call one of the exported functions. - In Linker/Addional Dependencies, I have added the .lib - In Linker/Additional Libray Directories, I have added the directory where is the lib. - In C/C++/General/Additional Include Directories, I have added the directory on project 1. I did that because I want to #include a header in Project_1. But, when I do that, I get:
T1 will never be 'nothing' T2 will only be 'nothing' if T3 also is 'nothing' (if it works with T3 not being nothing, that's fine, but it won't get used that way).
Portability is a non-issue, this only needs to work in VS (2010 and higher). The 'real' solution will need up to T10, I have a solution working with SFINAE, but it takes very very long to compile and it's getting very unwieldy if you would need to add T11.
I know it's not an ideal type approach, but it is what it is, this is a necessity due to linking with a legacy API which we don't have control over.
I am assigned this program by my instructor and he wants me to convert the function to function template. I do not know how to do that. How to get good grades in final.
I'm doing a homework aasignment on templates, and i have to build a list. The problem starts when i am trying to add elements to the list. For instance if i chose to add 5 different elements (1,2,3,4,5) the output will be (5,5,5,5,5).
I have this class templates And This UML.I have to write this function +operator=(source: Array<ElemType, SIZE>): Array<ElemType, SIZE> but I do not know how to start the declaration / or start the function. I have to return a template but I do not know how to do it,
I'm trying to create a callback wrapper for pointers to member functions of any class by using templates, std::function and std::bind. This will be used to send incoming sf::Event's to classes who register callbacks with an event manager. I based my code off of the example on this page: URL.....Here's what I have:
class EventCallback { std::function<bool(const sf::Event&)> func;
template<typename T> int compare(T &a,T &b); int compare(const char *a,const char *b); char ch_arr1[6]="world",ch_arr2[6]="hello"; compare(ch_arr1,ch_arr2);
After running the code above,we got to know the non-template function is called. What I know is that the array arguments ch_arr1,ch_arr2 will not be converted to char * because the parameters are references in the template functions.
ch_arr1,ch_arr2 need to be converted to const char * if compare(const char *a,const char *b) were called.
I just wanna know what exactly happened behind that? and why?
I understand template functions and how to call them explicitly when no arguments are passed to them but can't seem to instantiate them explicitly when it resides within a class or struct.
I was just wondering how is this generally resolved. Let say you have this large function that runs in two modes. In the first mode it evaluates the data passed to a function as a map the the second mode it fills the map. example:
Code: template <typename Map, typename Int> void func(Map & map, Int i){ int z = 0; string zz;
[Code] ....
The point is i do not want to write a large function just to include different modes so i decided to set "i" to be a mode identifier. However when i want to compile my function given two modes i get an error since the modes are not recognized (obviously). if i pass map as
Code: map<int,int> and mode 1 i get an error here : Code: map[z] = z; besause map Code: map[z] expects z to be an int not string and the other way around (though in practice this cannot happen since i set the modes). So am i restricted to writing my function for both modes separately (polimorf.) or there is a way to make my example work.
I want to have a template function that is a member of a class. Is this possible? This code snippet is how I would think the syntax would go, although it doesn't compile. How would I achieve the same effect?
Code: class myclass { public: int member ; } ; template <typename T> void myclass::func( T& arg )
I'm trying to pass the pointer of a dynamic array into a template function, but it keeps telling me there is no matching function to call because the parameters I'm passing in are wrong. how to make the function accept the pointer.
//main int main() { srand(unsigned(time(NULL))); int size; int *list; int *listCopy;
Pseudocode: template<typename T /*, some parameter for member_function */> class Foo { public: void someFunction() { T t; t.member_fuction(...); } }
I'm trying to make the call to T::member_function a templated value because member_function might vary by name in my scenario. Since std::mem_fn isn't a 'type', i can't do something like Foo<std::string, std::mem_fn(&std::string::clear)> foo;
I also want to take into account that member_function might have more than one parameter. That is, the first parameter will always be something known but there might be other defaulted parameters.
The only thing I can think of is to make a proxy structure, something like this:
I try to create small project in order to better understand how key word static works with templates . However some compiles errors crush my plan.
1>------ Build started: Project: 4.2b - Ex 1. Static Variable for Array Def Size. Templates, Configuration: Release Win32 ------ 1> main.cpp 1>c:all myс++ha level 6solution level 6solution level 64.2b - ex1. static variable for array def size. templatesarray.cpp(40): error C2724: 'Array<Type>:efaultSize' : 'static' should not be used on member functions defined at file scope