Why Python Multiprocessing Needs target=func Without Parentheses

Introduction

Hello, I'm Pipi. Yesterday I asked a question about Python multiprocessing in the "Python Diamond" group, and the discussion screenshot is shown below.

Below are the runtime screenshots of the issue:

Solution

User dcpeng provided an answer, illustrated in the following image:

The key point is that when creating a thread or process you must set target=function_name without parentheses.

1. Without parentheses, the function object itself is passed, so the thread runs the whole function without waiting for a return value.

2. With parentheses (and required arguments), the call executes the function and passes its return result, so the thread must wait for the function to finish.

Conclusion

This article reviews a basic Python multiprocessing issue, provides a concrete explanation and code implementation, thanks the participants, and invites readers to join the Python learning groups for further discussion.