常数
最后更新于：2022-04-02 02:33:06
[TOC]
## 示例
### 全局常量
```
#include
extern "C" {
PHPCPP_EXPORT void *get_module() {
static Php::Extension myExtension("my_extension", "1.0");
// floating point constants
myExtension.add(Php::Constant("MY_CONSTANT_3", 3.1415927));
// string constants
myExtension.add(Php::Constant("MY_CONSTANT_5", "This is a constant value"));
// null constants
myExtension.add(Php::Constant("MY_CONSTANT_7", nullptr));
// return the extension
return myExtension;
}
}
```
```
class Dummy : public Php::Base
{
};
extern "C"
{
PHPCPP_EXPORT void *get_module()
{
static Php::Extension myExtension("my_extension", "1.0");
Php::Class dummy("Dummy");
// 有三方方式给类赋值常量,
dummy.property("MY_CONSTANT_1", 1, Php::Const);
dummy.property("MY_CONSTANT_2", "abcd", Php::Const);
dummy.constant("MY_CONSTANT_3", "xyz");
dummy.constant("MY_CONSTANT_4", 3.1415);
dummy.add(Php::Constant("MY_CONSTANT_5", "constant string"));
dummy.add(Php::Constant("MY_CONSTANT_5", true));
// add the class to the extension
myExtension.add(std::move(dummy));
// return the extension
return myExtension;
}
}
```
### 运行时常量
在运行时从C ++代码中查找用户空间常量的值，或者要查找是否定义了常量，则可以简单地使用Php :: constant（）或Php :: define（）
void example_function()
{
//检查是否定义了某个用户空间常数
if (Php::defined("USER_SPACE_CONSTANT"))
{
//查找一个常量的值
Php::Value constant = Php::constant("ANOTHER_CONSTANT");
//在运行时定义其他常量
Php::define("DYNAMIC_CONSTANT", 12345);
}
}
extern "C"
{
PHPCPP_EXPORT void *get_module()
{
static Php::Extension myExtension("my_extension", "1.0");
myExtension.add("example_function", example_function);
return myExtension;
}
}
```
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