Update README.md

english/basic_content/extern/README.md

@@ -1,24 +1,24 @@
 # extern "C"
 
-## 关于作者：
+## About Author：
 
-个人公众号：
 
 ![](../img/wechat.jpg)
 
-## 1.C++与C编译区别
+## 1. Compiler difference between C and C ++
 
-在C++中常在头文件见到extern "C"修饰函数，那有什么作用呢？ 是用于C++链接在C语言模块中定义的函数。
+In C + +, we often see extern "C" modifier function in the header file. What's the effect. Is a function defined in C language module for C + + link.
 
-C++虽然兼容C，但C++文件中函数编译后生成的符号与C语言生成的不同。因为C++支持函数重载，C++函数编译后生成的符号带有函数参数类型的信息，而C则没有。
+Although C + + is compatible with C, the symbols generated by function compilation in C + + files are different from those generated by C language.Because C + + supports function overloading, the symbols generated by C + + function compilation have the information of function parameter type, while C does not.
 
-例如`int add(int a, int b)`函数经过C++编译器生成.o文件后，`add`会变成形如`add_int_int`之类的, 而C的话则会是形如`_add`, 就是说：相同的函数，在C和C++中，编译后生成的符号不同。
 
-这就导致一个问题：如果C++中使用C语言实现的函数，在编译链接的时候，会出错，提示找不到对应的符号。此时`extern "C"`就起作用了：告诉链接器去寻找`_add`这类的C语言符号，而不是经过C++修饰的符号。
+Take `int add(int a, int b)` for example. The C + + compiler generates the. O file, `add` becomes `add_int_int` and so on, while C would be like this `_add`, that is：For the same function, in C and C + +, the symbols generated after compilation are different.
 
-## 2.C++调用C函数
+This leads to a problem: if the function implemented in C + + is implemented in C language, an error will occur when compiling the link, indicating that the corresponding symbol cannot be found. At this time`extern "C"` works：Tell the linker to find its `_ C `language symbols such as `add` are not modified by C ++.
 
-C++调用C函数的例子: 引用C的头文件时，需要加`extern "C"`
+## 2.C ++ calls C functions
+
+When referring to the header file of C, you need to add `extern "C"`
 
 ```c++
 //add.h
@@ -44,20 +44,20 @@ int main() {
 }
 ```
 
-编译：
+Compile：
 
 ```
 //Generate add.o file
 gcc -c add.c
 ```
 
-链接：
+Link：
 
 ```
 g++ add.cpp add.o -o main
 ```
 
-没有添加extern "C" 报错：
+Without extern "C"：
 
 ```c++
 > g++ add.cpp add.o -o main                                   
@@ -71,7 +71,7 @@ add.cpp:(.text+0xf)：对‘add(int, int)’未定义的引用
 collect2: error: ld returned 1 exit status
 ```
 
-添加extern "C"后：
+With extern "C"：
 
 `add.cpp`
 
@@ -86,20 +86,20 @@ int main() {
     return 0;
 }
 ```
+When compiling, you must pay attention to generating intermediate files add.o through GCC
 
-编译的时候一定要注意，先通过gcc生成中间文件add.o。
 
 ```
 gcc -c add.c 
 ```
 
-然后编译：
+Compile：
 
 ```
 g++ add.cpp add.o -o main
 ```
 
-上述案例源代码见：
+Code：
 
 - [add.h](extern_c++/add.h)
 
@@ -107,9 +107,10 @@ g++ add.cpp add.o -o main
 
 - [add.cpp](extern_c++/add.cpp)
 
-## 2.C中调用C++函数
+## 2.Calling C++ function in C
 
-`extern "C"`在C中是语法错误，需要放在C++头文件中。
+
+`extern "C"` It is a syntax error in C, which needs to be put in the C + + header file.
 
 ```c
 // add.h
@@ -135,19 +136,19 @@ int main() {
 }
 ```
 
-编译：
+Compile：
 
 ```c
 g++ -c add.cpp
 ```
 
-链接：
+Link：
 
 ```
 gcc add.c add.o -o main
 ```
 
-上述案例源代码见：
+Code：
 
 - [add.h](extern_c/add.h)
 
@@ -155,11 +156,12 @@ gcc add.c add.o -o main
 
 - [add.cpp](extern_c/add.cpp)
 
-综上，总结出使用方法，在C语言的头文件中，对其外部函数只能指定为extern类型，C语言中不支持extern "C"声明，在.c文件中包含了extern "C"时会出现编译语法错误。所以使用extern "C"全部都放在于cpp程序相关文件或其头文件中。
+In the header file of C language, the external function can only be specified as extern type. The declaration of extern "C" is not supported in C language. There will be compiler syntax error when the. C file contains extern "C". Therefore, the use of external "C" is all placed in CPP program related files or its header files.
 
-总结出如下形式：
 
-（1）C++调用C函数：
+The following forms are summarized:
+
+（1）C + + calls C functions:
 
 ```c++
 //xx.h
@@ -176,7 +178,7 @@ extern "C" {
 }
 ```
 
-（2）C调用C++函数
+（2）C calls C + + functions
 
 ```c
 //xx.h