[Rd] on.exit() handler being interrupted by time limit
This StackOverflow question: https://stackoverflow.com/q/79594532 and
this discussion on Github: https://github.com/r-lib/evaluate/issues/242
are talking about an interesting situation.
Under a fairly simple setup shown in both, setTimeLimit() can interrupt
the on.exit() handler that was installed by evaluate::evaluate(),
leaving the system in a weird state.
Here's the setup:
If the document
```{r}
ans <- 6 * 7
Sys.sleep(2)
```
Answer: `r ans`
is saved in timeout.Rmd and then the code below is run you get weird
results, because plot hooks have been left in place:
```
setTimeLimit(elapsed = 1) # set a timeout
knitr::knit("timeout.Rmd") # knit the document which triggers it
print(1)# this works, but the hooks are still there
plot(1) # this triggers them
print(1)# Now this doesn't appear
```
What appears to be happening is that the timing error happens in the
middle of an on.exit() handler execution.
I'm not sure if this is being caused by the complicated way that
evaluate::evaluate() sets up the on.exit() handlers, or is being caused
by a problem in R.
BTW, the help for setTimeLimit() says that the time limit check happens
frequently during `Sys.sleep()`, but that doesn't appear to be true.
I've tried a variation on the code above which sleeps for 20 seconds,
even with a time limit of 1 second.
Duncan Murdoch
__
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[Rd] sqrt(.Machine$double.xmax)^2 == Inf, but only on Windows in R
Hello, Under R 4.5.0 on Windows (x86-64), I get: > sqrt(.Machine$double.xmax)^2 [1] Inf > sqrt(.Machine$double.xmax)*sqrt(.Machine$double.xmax) [1] Inf On other hand on other platforms, including Debian Linux (x86-64), I get: d> sqrt(.Machine$double.xmax)^2 [1] 1.797693134862315508561e+308 d> sqrt(.Machine$double.xmax)*sqrt(.Machine$double.xmax) [1] 1.797693134862315508561e+308 Windows is running inside a VirtualBox instance on the same host as Linux. I don't have direct results from the MacOS platforms, but based on the symptoms that had led me to investigate, the behaviour is as the Linux. Adding to the mystery, if I implement the same operation in C, e.g., library(inline) sqrsqrt <- cfunction(sig = c(x = "numeric"), language = "C", " double sqrtx = sqrt(Rf_asReal(x)); return Rf_ScalarReal(sqrtx*sqrtx); ") R on Linux yields: d> sqrsqrt(.Machine$double.xmax) [1] 1.797693134862315508561e+308 i.e., the same number, whereas R on Windows yields: d> sqrsqrt(.Machine$double.xmax) [1] 1.797693134862315508804e+308 which is not Inf but not the same as Linux either. Lastly, on both platforms, d> sqrsqrt(.Machine$double.xmax) < .Machine$double.xmax [1] TRUE I am not sure if this is a bug, intended behaviour, or something else. Best Regards, Pavel __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
