[Python-bugs-list] PyOS_AfterFork (PR#392)

[fdrake@beopen.com]

jon@dstc.edu.au writes:
 > In posixmodule.c:posix_fork, the function PyOS_AfterFork is called for
 > both the parent and the child, despite the docs stating that it should
 > be called in the new (child) process.
 > 
 > This causes problems in the parent since the forking thread becomes the 
 > main thread according to the signal module.
 > 
 > e.g. the following program fails with the frustrating message:
 > "ValueError: signal only works in main thread"

  After making the appropriate change in posixmodule.c, I get:


Exception in thread Thread-1:
Traceback (most recent call last):
  File "./../Lib/threading.py", line 376, in __bootstrap
    self.run()
  File "./../Lib/threading.py", line 364, in run
    apply(self.__target, self.__args, self.__kwargs)
  File "fork-signal.py", line 6, in foo
    os.wait(pid, 0)
TypeError: wait requires exactly 0 arguments; 2 given


  You're still right about the bug in posix_fork(), I think.  I'll
check in the fix (patch below) once someone else confirms this.
  Thanks for reporting this!


  -Fred

-- 
Fred L. Drake, Jr.  <fdrake at beopen.com>
BeOpen PythonLabs Team Member

Index: Modules/posixmodule.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Modules/posixmodule.c,v
retrieving revision 2.141
diff -c -r2.141 posixmodule.c
*** Modules/posixmodule.c	2000/06/30 23:58:05	2.141
--- Modules/posixmodule.c	2000/07/06 05:43:33
***************
*** 1755,1761 ****
  	pid = fork();
  	if (pid == -1)
  		return posix_error();
! 	PyOS_AfterFork();
  	return PyInt_FromLong((long)pid);
  }
  #endif
--- 1755,1762 ----
  	pid = fork();
  	if (pid == -1)
  		return posix_error();
! 	if (pid == 0)
! 		PyOS_AfterFork();
  	return PyInt_FromLong((long)pid);
  }
  #endif