Python | os.WTERMSIG() method

OS module in Python provides functions for interacting with the operating system. OS comes under Python’s standard utility modules. This module provides a portable way of using operating system dependent functionality.
os.WTERMSIG() method in Python is used to get the signal number which caused the process to exit. This method takes process status code as returned by os.wait(), os.system() or os.waitpid() method as a parameter.

Syntax: os.WTERMSIG(status)
Parameters:
status: This parameter takes process status code (an integer value) as returned by os.system(), os.wait() or os.waitpid() method. 
Return type: This method returns an integer value which represent the signal number which caused the process to exit. 

Code #1: Use of os.WTERMSIG() method 

Python3

# Python program to explain os.WTERMSIG() method

# importing os and signal module
import os, signal

# Create a child process
# using os.fork() method
pid = os.fork()


# pid greater than 0
# indicates the parent process
if pid :

    # Wait for the completion of
    # the child process and get
    # its pid and
    # exit status indication
    info = os.wait()

    # info is a tuple
    # info[0] represents child's id
    # info[1] represents exit status code

    print("\nIn parent process")

    # Get the signal number which caused
    # the child process to exit
    sig_num = os.WTERMSIG(info[1])

    print("Child process exited due to signal no:", sig_num )

    # We can get the signal name
    # corresponding to the signal number
    # in following way
    print("Signal name:", signal.Signals(sig_num).name)
else :
    print("In Child process")
    print("Process ID:", os.getpid())
    print("Hello ! Geeks")

    # os.abort() method will
    # generate a SIGABRT signal
    # to the current process
    # and will produce core dump.
    os.abort()

Output:

In Child process
Process ID: 3421
Hello! Geeks

In parent process
Child process exited due to signal no: 6
Signal name: SIGABRT

Code #2: Use of os.WTERMSIG() method 

Python3

# Python program to explain os.WTERMSIG() method

# importing os and signal module
import os, signal

# Create a child process
# using os.fork() method
pid = os.fork()


# pid greater than 0
# indicates the parent process
if pid :

    # Create one more child
    pid2 = os.fork()

    if pid2 :


        # Wait for the completion of
        # first child process and get
        # its pid and
        # exit status indication
        # using os.waitpid() method
        child1_info = os.waitpid(pid, 0)

        # Wait for the completion of
        # second child process and get
        # its pid and exit status indication
        # using os.waitpid() method
        child2_info = os.waitpid(pid2, 0)

        # os.waitpid() method
        # returns a tuple which
        # represents child's pid
        # and exit status code

        print("\nIn parent process")
        # Get the signal number which caused
        # first child process to exit
        sig_num = os.WTERMSIG(child1_info[1])
        if sig_num != 0 :
            print("First child process exited due to signal no:", sig_num )
            print("Signal name:", signal.Signals(sig_num).name)
        else:
            print("First child exited normally")

        # Get the signal number which caused
        # second child process to exit
        sig_num = os.WTERMSIG(child2_info[1])
        if sig_num != 0 :
            print("Second child process exited due to signal no:", sig_num )
            print("Signal name:", signal.Signals(sig_num).name)

        else:
            print("Second child exited normally")

        # sig_num equal to 0 represents
        # that no signal caused
        # the process to exit

    else :
        print("\nIn second child process")
        print("Process id:", os.getpid())
        print("Hey ! there")
        print("Exiting..")

else :
    print("In first child process")
    print("Process ID:", os.getpid())
    print("Hello ! Geeks")

    # os.abort() method will
    # generate a SIGABRT signal
    # to the current process
    os.abort()

Output:

In First child process
Process ID: 3752
Hello! Geeks

In second child process
Process id: 3753
Hey! there
Exiting..

In parent process
First child process exited due to signal no: 6
Signal name: SIGABRT
Second child exited normally

References: https://docs.python.org/3/library/os.html#os.WTERMSIG