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std::unique_ptr with an incomplete type won't compile
...If you use pimpl with unique_ptr, you need to declare a destructor:
class foo
{
class impl;
std::unique_ptr<impl> impl_;
public:
foo(); // You may need a def. constructor to be defined elsewhere
~foo(); // Implement (with {}, or with = default;) where impl is complete
};
...
Is there a difference between foo(void) and foo() in C++ or C?
...
In C:
void foo() means "a function foo taking an unspecified number of arguments of unspecified type"
void foo(void) means "a function foo taking no arguments"
In C++:
void foo() means "a function foo taking no arguments"
void...
How to load all modules in a folder?
...
Update in 2017: you probably want to use importlib instead.
Make the Foo directory a package by adding an __init__.py. In that __init__.py add:
import bar
import eggs
import spam
Since you want it dynamic (which may or may not be a good idea), list all py-files with list dir and import them...
Django REST Framework: adding additional field to ModelSerializer
...
I think SerializerMethodField is what you're looking for:
class FooSerializer(serializers.ModelSerializer):
my_field = serializers.SerializerMethodField('is_named_bar')
def is_named_bar(self, foo):
return foo.name == "bar"
class Meta:
model = Foo
fields = ('id', 'na...
scoped_ptr 与 auto_ptr 与 shared_ptr 区别总结 - C/C++ - 清泛网 - 专注C/C++及内核技术
...lude <memory>
#include <iostream>
using std::tr1::shared_ptr;
class Foo
{
public:
Foo()
{
std::cout<<"new Foo()"<<std::endl;
i = 0;
}
~Foo()
{
std::cout<<"destroy Foo()"<<std::endl;
}
void print()
{
std::cout<<"Foo::print"<<std::endl;
}
int i;
};
void...
Callback functions in C++
...rguably the worst) type a callback can have.
Let's have a simple function foo:
int foo (int x) { return 2+x; }
1.1 Writing a function pointer / type notation
A function pointer type has the notation
return_type (*)(parameter_type_1, parameter_type_2, parameter_type_3)
// i.e. a pointer to foo...
Why do function pointer definitions work with any number of ampersands '&' or asterisks '*'?
...ay.
The fundamental reason why all of these work is that a function (like foo) is implicitly convertible to a pointer to the function. This is why void (*p1_foo)() = foo; works: foo is implicitly converted into a pointer to itself and that pointer is assigned to p1_foo.
The unary &, when app...
Calling C/C++ from Python?
...e you have a simple C++ example class you want to talk to in a file called foo.cpp:
#include <iostream>
class Foo{
public:
void bar(){
std::cout << "Hello" << std::endl;
}
};
Since ctypes can only talk to C functions, you need to provide those de...
Using Mockito to mock classes with generic parameters
...d of mocking a class with generic parameters? Say I have to mock a class Foo<T> which I need to pass into a method that expects a Foo<Bar> . I can do the following easily enough:
...
Extending from two classes
...aven't really gone into how. Hopefully this will help.
Say you have class Foo and class Bar that you both want to try extending into a class FooBar. Of course, as you said, you can't do:
public class FooBar extends Foo, Bar
People have gone into the reasons for this to some extent already. Inste...