大约有 6,261 项符合查询结果（耗时：0.0187秒） [XML]
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...
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...
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...
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...
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...
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:
...