Python Multi-process--fork () __python

1, Linux under the fork ()
Usage: Import OS
Help (Os.fork):
Functions built into Linux modules fork:
Fork (): derives a child process.
Child process returns 0
PID for the parent process to return the child process
Cases:

  Import OS
# Note that the fork function, only run on Unix/linux/mac, Windows can not be
  pid = os.fork ()
  If pid = 0:
      print (' haha 1 ')
   else:
      print (' Haha 2 ')

results:
        haha 2
        haha 1

Description
When a program executes to Os.fork (), the operating system creates a new process (subprocess), and then copies all the information from the parent process into the child process
Both the parent process and the subprocess then get a return value from the fork () function, which must be 0 in the child process, and the ID number of the child process in the parent process.

2, Os.getpid (), Os.getppid ()
Os.getpid (): Returns the PID of the current process
Os.getppid (): Returns the PID of the parent process of the current process

3, multiple fork problems

Cases:

#coding =utf-8
import os
import time

# Note that the fork function, run only on Unix/linux/mac, Windows cannot be
pid = os.fork ()
If PID = = 0:
    print (' haha 1 ')
else:
    print (' Haha 2 ')

pid = os.fork ()
If pid = 0:
    print (' haha 3 ')
else:
    print (' haha 4 ')

Time.sleep (1)

Results:

Description