1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
|
<h1>Classes and objects</h1>
<p>
Serious business now. C++ and PHP are both object oriented programming
languages, in which you can create classes and objects, and the PHP-CPP library
gives you the tools to combine these two and make a native C++ class
accessible from PHP.
</p>
<p>
Sadly (but also logically) not every thinkable C++ class can be directly
exported to PHP. It takes a little more work (although not so much). For a
start, you must make sure that your class is derived from Php::Base, and
secondly, when you add your class to the extension object, you must also
specify all methods that you want to make accessible from PHP.
</p>
<p>
<pre class="language-c++"><code>
#include <phpcpp.h>
// actual class implementation
class Counter : public Php::Base
{
private:
int _value = 0;
public:
MyClass() {}
virtual ~MyClass() {}
Php::Value increment() { return ++_value; }
Php::Value decrement() { return --_value; }
Php::Value value() const { return _value; }
};
extern "C" {
PHPCPP_EXPORT void *get_module() {
static Php::Extension myExtension("my_extension", "1.0");
// description of the class so that PHP knows which methods are accessible
Php::Class<Counter> counter("Counter");
counter.method("increment", &Counter::increment)
counter.method("decrement", &Counter::decrement)
counter.method("value", &Counter::value)
// add the class to the extension
myExtension.add(std::move(counter));
// return the extension
return myExtension;
}
}
</code></pre>
</p>
<p>
The above example shows a very simple Counter class with three methods:
increment(), decrement() and value(). The two update methods return the value
of the counter after the operation, the value() method returns the current value.
</p>
<p>
If you want to make a class method that is accessible from PHP, you must
ensure that is has one of the four supported signatures (which are the same
signatures that <a href="functions">exportable plain functions</a> should have):
</p>
<p>
<pre class="language-c++"><code>
void YourClass::example1();
void YourClass::example2(Php::Parameters &params);
Php::Value YourClass::example3();
Php::Value YourClass::example4(Php::Parameters &params);
</code></pre>
</p>
<p>
In the example we have used the third method form, a method that does
not take any parameters, and that returns a Php::Value object. The methods
work exactly the same as regular functions, with the difference that they
are methods so you have access to a this pointer that refers to the current
object.
</p>
<p>
To make the class accessible from PHP, you must add it to the extension
object. The Php::Class object can be be used for that. This is a templated
class. The template parameter should be your implementation class, so that
the Php::Class object internally knows which class to instantiate the moment
the "new" operator is used inside a PHP script.
</p>
<p>
The Php::Class constructor receives a string parameter, with the name of
class in PHP. After you've created an instance of the Php::Class object,
you should specify all methods that you want to make accessible from PHP,
and finally, when all methods have been registered, you should add the
class to your extension object so that it will be accessible from PHP.
Note that in our example we have used the C++11 std::move function, so
that the class object is actually <i>moved</i> into the extension object,
which is a more efficient operation than copying.
</p>
|
