[R] vcov method for 'coxph' objects

[Vito Muggeo]

Dear all,
The help file for the generic function vcov states

"Classes with methods for this function include: 'lm', 'glm', 'nls', 'lme',
'gls', 'coxph' and 'survreg' (the last two in package 'survival')."

Since, I am not able to use vcov.coxph(), I am wondering whether I am
missing something (as I suspect..)

regards,
vito

library(survival)
> o<- coxph( Surv(time, status) ~ x + strata(sex), test1)  #example from
?coxph
> vcov(o)  #of course I could use o$var
Error in vcov(o) : no applicable method for "vcov"
> R.version
         _
platform i386-pc-mingw32
arch     i386
os       mingw32
system   i386, mingw32
status
major    2
minor    0.0
year     2004
month    10
day      04
language R