Stas Bekman wrote:
Malte Ubl wrote:
[...]
Our code is not using any specials variables though except %SIG for
alarm.
I've used $$ just as an example, any variable can be affected.
How does a variable become read-only? Is that something that can be
done on C/XS Level?
Yes. By setting the READONLY flag on the scalar. But it may happen as a
result of some bug.
You also get a readonly variable if it's not a variable but a constant,
e.g.:
perl -MDevel::Peek -le 'Dump "aaa"'
SV = PV(0x804c4a0) at 0x805b88c
REFCNT = 1
FLAGS = (POK,READONLY,pPOK)
PV = 0x805e420 "aaa"\0
CUR = 3
LEN = 4
so for example if a function receives a string as an argument, e.g.,
foo("aaa") and then the function tries to modify its $_[0]'s argument
you will get this error.
We made this test on the production system where the error seems to
occur on about 50% of the occassions described in my older mails.
We introduced a #line statement which gives conclusive results pointing
to this line in PerlRun.pm:
$pr->{'code'} = $pr->{r}->slurp_filename; # this is line 215
Then we pumped $pr using Devel::Peek. The result is:
<dump>
SV = RV(0x87893e4) at 0x8461c04
REFCNT = 1
FLAGS = (PADBUSY,PADMY,ROK)
RV = 0x8f7082c
SV = PVHV(0x90e0b18) at 0x8f7082c
REFCNT = 2
FLAGS = (OBJECT,SHAREKEYS)
IV = 3
NV = 0
STASH = 0x83aebe4 "Apache::PerlRun"
ARRAY = 0x9165db0 (0:6, 1:1, 2:1)
hash quality = 90.0%
KEYS = 3
FILL = 2
MAX = 7
RITER = -1
EITER = 0x0
Elt "namespace" HASH = 0xb25e00b2
SV = PV(0x915e728) at 0x8fcedd4
REFCNT = 1
FLAGS = (POK,pPOK)
PV = 0x9197b00 "Apache::ROOTappsrv2::bin::rpc_2dxml_2emplr"\0
CUR = 42
LEN = 43
Elt "r" HASH = 0x26014be2
SV = RV(0x8789250) at 0x8f6dce8
REFCNT = 1
FLAGS = (ROK)
RV = 0x8fa6a98
SV = PVMG(0x9156468) at 0x8fa6a98
REFCNT = 3
FLAGS = (OBJECT,IOK,pIOK)
IV = 137085032
NV = 0
PV = 0
STASH = 0x82eb0b4 "Apache"
Elt "mtime" HASH = 0x1c616a53
SV = NV(0x904ba10) at 0x8fcef9c
REFCNT = 1
FLAGS = (NOK,pNOK)
NV = 108.194803240741
</dump>
There doesn't seem to be anything read-only here?
One extra piece of information: The app that we ported to mod_perl uses
file-locks (flock) using type glob (pre perl 5.6 style) file handles.
Could this error occur if the close or unlock a type glob that does not
have a file handle in it?
Thanks
Malte
--
SCHAFFHAUSEN COMMUNICATION GROUP
Schaffhausen Advertising GmbH / Daimlerstraße 17 / 25337 Elmshorn
Fon +49 41 21.47 29-459 / Fax +49 41 21.47 29-455
[EMAIL PROTECTED] / www.schaffhausen.de
