CODEWITHSUNDEEP
pythonmacossignals
Alex
Alex

Reputation: 44325

How to fix 'Bus Error' in python code to receive a signal?

I created a python code following this description:

import os
import time
import signal

def receiveSignal(signalNumber, frame):
    print('Received:', signalNumber)
    return

signal.signal(signal.SIGUSR1, receiveSignal)

# output current process id
print('My PID is:', os.getpid())

# wait in an endless loop for signals
while True:
    print('Waiting...')
    time.sleep(3)

which runs fine. But when I try to send a SIGUSR1 signal from another terminal, e.g. :

kill -10 55947

the python code fails as follows:

My PID is: 55947
Waiting...
Waiting...
Bus error: 10

The code is running on MacOS 10.13.6, and I tried using python 2.7.12 and python 3.6.2. In both cases I get that Bus Error.

Is there a way to fix that? Maybe this is a mac issue? I expect the running code to execute the method receiveSignal, but otherwise stay in the shile loop.

Upvotes: 0

Views: 1467

Answers (1)

han solo
han solo

Reputation: 6590

I think, the problem is, in MacOS, the SIGNAL 10 means SIGBUS.

See the signal list https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man3/signal.3.html

See the signal details,

     1     SIGHUP       terminate process    terminal line hangup
     2     SIGINT       terminate process    interrupt program
     3     SIGQUIT      create core image    quit program
     4     SIGILL       create core image    illegal instruction
     5     SIGTRAP      create core image    trace trap
     6     SIGABRT      create core image    abort program (formerly SIGIOT)
     7     SIGEMT       create core image    emulate instruction executed
     8     SIGFPE       create core image    floating-point exception
     9     SIGKILL      terminate process    kill program
     10    SIGBUS       create core image    bus error
     ...
     ...
     30    SIGUSR1      terminate process    User defined signal 1
     31    SIGUSR2      terminate process    User defined signal 2

Hence, the error.

Try sending SIGNAL 30, and see :)

Upvotes: 1

Related Questions