How does javascript call the c interface

Before discussing how to call the C interface, we need to first understand what the C interface is. C interface usually refers to a program interface written in C language that can be called by other languages. This interface is usually provided in the form of a shared library or DLL, allowing other languages ​​(such as JavaScript) to call C functions through the interface.

Calling the C interface in JavaScript requires the use of a technology called "external mechanism". This technique enables JavaScript code to interact with the underlying operating system and allows JavaScript code to access C functions located in shared libraries.

Below we will introduce some basic steps to use JavaScript to call the C interface.

Step One: Create a C Interface

First, we need to create a C interface so that it can be called by JavaScript. This can be done by using a C compiler to create a dynamic library or using a DLL. When creating a C interface, we need to ensure that the library and function names are correctly specified, and that the function parameters are correct.

The following is a simple C function example whose purpose is to add two integers and return the result:

int add(int a, int b)
{
    return a + b;
}

Step 2: Create a JavaScript object

Connect Next, we need to create a JavaScript object to represent the C function interface. We can use properties in JavaScript objects to set C library and function names, as well as information such as function parameters and return types. For ease of explanation, the following code examples assume that the interface function library is located locally and is named "mylib".

// 创建一个对象来表示C函数接口
var module = {
    name: "mylib",
    funcs: {
        // 设置函数名称、参数和返回类型
        "add": {
            "args": [ "int", "int" ],
            "result": "int"
        }
    }
};

Step 3: Write JavaScript code to call the C interface

Now we can write JavaScript code to call the C function using the module object we created previously. Before calling the C function, we need to ensure that the required libraries are loaded correctly. Once we are sure that we have loaded the library correctly, we can call the C function with code similar to the following:

// 加载C函数库
var cModule = ctypes.open(module.name + ".dll");
// 获取接口函数
var addFunc = cModule.declare(module.funcs.add.name, ctypes.default_abi, ctypes.int, module.funcs.add.args);
// 调用接口函数
var result = addFunc(1, 2);
// 输出结果
console.log(result);

The above code first uses the ctypes.open method to open the library file we created previously, and then uses cModule .declare method to get the pointer of the add function. Finally, we use the addFunc pointer to call the add function and store the result in a variable. This result is the result of adding 1 and 2 (that is, 3), and we can use console.log to output it.

Summary:

In this article, we introduced the basic steps of using JavaScript to call the C interface. We first created the C function interface, created an object in JavaScript to represent it, and finally wrote JavaScript code to call the interface function. If you are interested in how to use JavaScript to call C interfaces, I hope this article will be helpful to you.

The above is the detailed content of How does javascript call the c interface. For more information, please follow other related articles on the PHP Chinese website!