bug (Incorrect signal processing) - Python 1.5.2 #32663

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1. nobody commented on Jul 31, 2000

   

   nobodymannequin

   on Jul 31, 2000

   Mannequin

   More actions

   Jitterbug-Id%3
   a 102
   Submitted-By: "=?iso-8859-2?B?VmxhZGlt7XIgQmVuZbk=?=%2
   2 <Vladimir.Benes@pvt.cz>
   Date: Mon, 11 Oct 1999 13:00:07 +0200%
   0aVersion: None
   OS: None

   Good afternoon,

   I have found a bug 
   

   on Python 1.5.2. This bug doesn't occur on Python
   1.5.1.

   Python version
   s and OS:

   • Python 1.5.1. at Debian GNU/Linux 2.0.36
   • Python 1.5.2. at De
     bian GNU/Linux 2.2.9

   Bug: Incorrect signal processing (Python 1.5.2).

   Process can assign procedure for signal processing. When process is
   

   wai
   ting at system call and this signal occur, then the signal assigned
   procedure
   is otherwise correctly completed but then waiting at system call
   is broken and
   process continues.

   Here is a simple program for demonstrate this bug:
   

   #!/usr/bin/python
   import signal
   import sys
   
   def signal_handle
   (signum, frame) :
     signal.signal(signal.SIGALRM, signal_handle)
    
    signal.alarm(2)
     print "signal"
   
   signal_handle(0,0)
   a=sys.stdin.readline()
   print "Line examined..."
   b=sys.stdin.readline%2
   8)
   print "Line examined..."
   print a,b,"end"
   # end of example

   Correct behaviour: Message "Line examined..." occurs only after pr
   

   essing
   ENTER by user.
   Bug: Message "Line examined..." occurs immed
   iately after signal occured
   and procedure signal_handle finished. Output then look thus (when no input
   entered):

   signal
   signal
   Line examined.
   ..
   signal
   Line examined...
   end

   This bug appears at any signal o
   

   ccur and whatever process waiting at
   system call. Some system call even produces exception (e.g. waiting for data
   or connection on socket).

   Bug
   

   is perhaps caused by wrong seting "siginterrupt" on module signal. I
   have
   n't found any way how call in Python program "siginterrupt" for correct
   behavior of signal processing.

       Good bye, V. Benes
   

   ---

   %2
   a%
   2a******************
   Ing. Vladimir Benes, pvt.net
   PVT, a.s., OZ Chomutov
   e-mail: vladimir.benes@pvt.cz
   , vladimir.benes@sms.paegas.cz

   ---

   **********************************************%
   2a

   Audit trail:
   Mon Oct 11 18:12:13 1999
   guido moved from incoming to open
2. anonymous

   closed this as completedon Jul 31, 2000
3. anonymous

   added

   invalid

   on Jul 31, 2000
4. ezio-melotti

   transferred this issue fromon Apr 9, 2022