How to use C ++ to call the C-Linked Library

The C ++ programming language is widely used and has flexible application methods. It supports multiple programming styles and helps us solve many problems easily. For example, the specific operation method for C ++ to call the C link library introduced today is a classic example, which allows you to fully understand the concept.

• Detailed description of how C ++ generates random numbers
• Practical application skills of C ++ linked list operations
• A Brief Introduction to the C ++ Operating Mechanism
• Basic concepts of C ++ cyclic statements
• Application Methods for C ++ class members

C ++ calls the C link library, but it actually calls C ++ relative to C. Because C ++ is inherently backward compatible with C's personal opinions ).

However, due to the different design of the compiler, some problems may occur, such as: In the middle part, there is an undefined reference to 'helloc () ', helloC () is my function in the C-Linked Library)

Simply put, the reason is that the function name may change to _ helloC () after the unprocessed C code is compiled, but the function name after the C ++ compilation is not like this, so it is not correct.

You need to add extern "C" to the include c file"

In the exercise, three files are written: c. h c. c cpp. The first two files are compiled as C-linked libraries, and cpp. cpp uses C. It verifies that C ++ calls the C link library to access the global variables of C.

C. h:

 
 

  
  
#include "stdio.h"  
  
  
void helloC();  
  
  
int abc = 1; 
 
 

C. c:

 
 

  
  
#include <stdio.h> 
  
  
#include "c.h"  
  
  
void helloC(){  
  
  
printf("I am Kenko");  
  
  
} 
 
 

Cpp. cpp: (focus on include)

 
 

  
  
#include <iostream> 
  
  
using namespace std;  
  
  
extern "C" {  
  
  
#include "c.h"  
  
  
}  
  
  
int main(){  
  
  
helloC();  
  
  
cout<<abc<<endl;  
  
  
return 0;  
  
  
} 
 
 

This section describes how C ++ calls the C-Linked Library.