stdout not flushed before os.execvp()

[Thomas Guettler]

Hi,

I noticed, that sys.stout does not get flushed before the process is
replaced. The last print statements (before execvp()) disappear.

It only happens, if the output is redirected to a file (if sys.stdout is
not line buffered).

"""#testexe c.py
import os
print "Messsage"
os.execvp("/bin/true", ["/bin/true"])
"""

===python tmp/testexec.py
Messsage

===python tmp/testexec.py out ; cat out


Is this a bug or feature?

My version:
Python 2.4.2 (#1, May 2 2006, 08:28:01)
GCC 4.1.0 (SUSE Linux)] on linux2


--
Thomas Güttler, http://www.thomas-guettler.de/ http://www.tbz-pariv.de/
E-Mail: guettli (*) thomas-guettler + de
Spam Catcher: niemand.leerman n@thomas-guettler.de

[Fredrik Lundh]

Re: stdout not flushed before os.execvp()

Thomas Guettler wrote:

Is this a bug or feature?

feature. the "exec" system call operates on a lower level than the
stdio buffering system.

</F>

[dakman@gmail.com]

Re: stdout not flushed before os.execvp()

If you wanted to make sure stdio was flushed you could always do...

sys.stdout.writ e("Message\n" )
sys.stdout.flus h()

Thomas Guettler wrote:

Hi,
>
I noticed, that sys.stout does not get flushed before the process is
replaced. The last print statements (before execvp()) disappear.
>
It only happens, if the output is redirected to a file (if sys.stdout is
not line buffered).
>
"""#testexe c.py
import os
print "Messsage"
os.execvp("/bin/true", ["/bin/true"])
"""
>
===python tmp/testexec.py
Messsage
>
===python tmp/testexec.py out ; cat out
>
>
Is this a bug or feature?
>
My version:
Python 2.4.2 (#1, May 2 2006, 08:28:01)
GCC 4.1.0 (SUSE Linux)] on linux2
>
>
--
Thomas Güttler, http://www.thomas-guettler.de/ http://www.tbz-pariv.de/
E-Mail: guettli (*) thomas-guettler + de
Spam Catcher: niemand.leerman n@thomas-guettler.de

[Fulvio]

Re: stdout not flushed before os.execvp()

On Wednesday 18 October 2006 00:25, Fredrik Lundh wrote:

|feature. the "exec" system call operates on a lower level than the
|stdio buffering system.

I did in this manner:

for exe in ('imap4', 'pop3'):
if exe in cfgfil[optsrv + '.protocol']:
exe = exe[:4]; exe = 'call_func = _call_' + exe.upper() \
+ '(setting)'
try:
exec exe
except ProtocolError:
call_func = '#ERROR 02 = Protocol failed with %s' %optsrv
break

exists it a different way to do it?

F