traceback.print_exc() supposed to stop exception propagation.

[Sami]

Hello,

In the Python book that I am using to learn the language it says that
the traceback.print _exc() can be used to stop exception propagation and
make the program keep running.

Here is a simple piece of code that I typed in to test this fact:
---------------------------------------------------------------------------
import sys

def Myexcepthook(et ype, value, tb):
print "in Myexcepthook\n"
import traceback
lines=traceback .format_excepti on(etype, value, tb)
print "\n".join(lines )
traceback.print _exc()


sys.excepthook = Myexcepthook

x = 1/0

x = 78

print x
--------------------------------------------------------------------------
The Output:
--------------------------------------------------------------------------
in Myexcepthook

Traceback (most recent call last):

File
"E:\Home\Progra mming\Python\Tr yProjects\Excep tHandling1\Exce pt2.py", lin
15, in <module>
x = 1/0

ZeroDivisionErr or: integer division or modulo by zero

None
--------------------------------------------------------------------------

I never see the value 78.

What am I doing wrong?

Thanks,
Sami

[Diez B. Roggisch]

Re: traceback.print _exc() supposed to stop exception propagation.

Sami schrieb:

Hello,
>
In the Python book that I am using to learn the language it says that
the traceback.print _exc() can be used to stop exception propagation and
make the program keep running.
>
Here is a simple piece of code that I typed in to test this fact:
---------------------------------------------------------------------------
import sys
>
def Myexcepthook(et ype, value, tb):
print "in Myexcepthook\n"
import traceback
lines=traceback .format_excepti on(etype, value, tb)
print "\n".join(lines )
traceback.print _exc()
>
>
sys.excepthook = Myexcepthook
>
x = 1/0
>
x = 78
>
print x
--------------------------------------------------------------------------
The Output:
--------------------------------------------------------------------------
in Myexcepthook
>
Traceback (most recent call last):
>
File
"E:\Home\Progra mming\Python\Tr yProjects\Excep tHandling1\Exce pt2.py", lin
15, in <module>
x = 1/0
>
ZeroDivisionErr or: integer division or modulo by zero
>
None
--------------------------------------------------------------------------
>
I never see the value 78.
>
What am I doing wrong?

Trusting a wrong source. Or misinterpreting it.

Python 2.5.1 (r251:54863, May 2 2007, 16:56:35)
[GCC 4.1.2 (Ubuntu 4.1.2-0ubuntu4)] on linux2
Type "help", "copyright" , "credits" or "license" for more information.
imWelcome to rlcompleter2 0.96
for nice experiences hit <tabmultiple times

>>import traceback
>>help(tracebac k.print_exc)

Help on function print_exc in module traceback:

print_exc(limit =None, file=None)
Shorthand for 'print_exceptio n(sys.exc_type, sys.exc_value,
sys.exc_traceba ck, limit, file)'.
(In fact, it uses sys.exc_info() to retrieve the same information
in a thread-safe way.)

>>>

Nothing in there says that this would prevent the exception from being
propagated.

Diez

[Terry Reedy]

Re: traceback.print _exc() supposed to stop exception propagation.


"Sami" <sami.islam@NOS PAMbtinternet.c omwrote in message
news:69-dnW_JftMHvGTanZ 2dneKdnZydnZ2d@ bt.com...
| Hello,
|
| In the Python book that I am using to learn the language it says that
| the traceback.print _exc() can be used to stop exception propagation and
| make the program keep running.

It is possible that the unspecified book describes an unspecified Python
version that is not the same as the unspecified version that you tested
with ;-).

Help respondants by providing version info. Sometimes even the system/OS
info is helpful, though probably not relevant here.

tjr