Creation process of Python system programming

I. Forking process

The process produced by fork has the following characteristics:

• is a clone of a process.
• The created process exists independently of the parent process.
• The thread is copied to execute at the call fork ().
  
  • Returns 0 in the child thread.
  • Returns the PID of the child thread in the parent thread
  • The PID of a child thread differs from the parent thread.

Second, code example

#!/usr/bin/env pythonImportOs def child_process():    Print "I am the child process and my PID are:%d"% Os.getpid ()Print "teh child is exiting." def parent_process():    Print "I am the parent process whit PID:%d"% os.getpid () childID = Os.fork ()ifchildID = =0:#在子进程中Child_process ()Else:#在父进程中        Print "Inside the parent process"        Print "My child's PID is:%d"% childID while True:PassParent_process ()

When the child thread ends, the parent thread is still running and is not rolled out.

Third, mass production of new threads

• Os.exec* Series functions
  
  • Os.execl
  • Os.execle
  • Os.execvp
• Child process Overrides parent process
  

You can see that a process created in this way overrides the parent process, and the parent process ends when the child process ends.

Creation process of Python system programming