How to call a C library function that returns a function pointer in ctype?
Table of Contants
Introduction
Calling a C library function that returns a function pointer in Python can be accomplished using the ctypes library. This process allows you to utilize complex C functions in your Python applications, enabling powerful integrations. This guide will provide step-by-step instructions on how to define the appropriate function prototypes and call a C library function that returns a function pointer.
Steps to Call a C Library Function That Returns a Function Pointer
Step 1: Define the C Function
First, you need a C function that returns a function pointer. Below is an example of such a function.
- C Code (function_pointer.c):
Step 2: Compile the C Code
Compile the C code into a shared library that Python can access
Step 3: Load the Shared Library in Python
Now that you have your shared library, you can load it using ctypes.
Step 4: Define Function Prototypes
You need to define the function prototypes for both the function that returns the function pointer and the function pointer type itself.
- Define Function Pointer Type:
- Define the Function Prototype for get_add_function:
Step 5: Create an Instance of the Function Prototype
Create an instance of the function prototype for the C function that returns the function pointer.
Invoke the get_add_function to retrieve the function pointer.
Step 7: Call the Returned Function Pointer
Now that you have the function pointer, you can call it as if it were a regular Python function.
Practical Example
Full Python Example
Here's the complete Python code that calls the C library function returning a function pointer:
Conclusion
Calling a C library function that returns a function pointer using ctypes in Python involves defining the appropriate function prototypes and utilizing the function pointer effectively. By following the steps outlined in this guide, you can easily integrate complex C functionality into your Python applications, enhancing their capabilities. This process opens up numerous possibilities for leveraging existing C code in a Python environment.