similar to: system/system2 and open file descriptors

In addition to the issue of a child process holding onto open files, the child process can also manipulate a file descriptor in a way that affects the parent process. For example, calling lseek() in the child process will move the file offset in the parent process. Here is a set of commands that demonstrates it. They can be copied and pasted in a terminal. What it does: - Creates C program that

I ran into this and found the result very surprising: identical( quote({ a }), quote({ a }) ) # FALSE It seems related to curly braces. For example, parens work fine: identical( quote(( a )), quote(( a )) ) # TRUE Is this expected behavior? I can't seem to find anything in the help for identical that relates to this. -Winston

On Wed, Apr 29, 2015 at 12:53 PM, Winston Chang <winstonchang1 at gmail.com> wrote: > On Tue, Apr 28, 2015 at 3:04 PM, G?bor Cs?rdi <csardi.gabor at gmail.com> > wrote: > > > > > > E.g. if package 'ggplot2' uses 'stats::density()', and package 'igraph' > > also defines 'density()', and 'igraph' is on the search

>>>>> Winston Chang <winstonchang1 at gmail.com> >>>>> on Fri, 23 Jan 2015 10:15:53 -0600 writes: > I think you can simplify a little by replacing this: > pkg %in% loadedNamespaces() > with this: > .getNamespace(pkg) almost: It would be !is.null(.getNamespace(pkg)) > Whereas getNamespace(pkg) will load the

Hi all, Profiling turned up a bit of a speedbump in the library function. I submitted a patch to the R bug tracker as bug 16168 and I've also included it below. The alternate code is simpler and easier to read/maintain, I believe. Any thoughts on other ways to write this? Index: src/library/base/R/library.R =================================================================== ---

When a reference class method is accessed with .self$x, it has different behavior from .self[['x']]. The former copies the function to the object's environment (with some attributes attached), and the latter just return NULL (unless it has already been accessed once with .self$x). Is this how it's supposed to work? Here's an example that illustrates:

) On Wed, Apr 5, 2017 at 2:59 AM, Martin Maechler <maechler at stat.math.ethz.ch> wrote: > > >>>>> Winston Chang <winstonchang1 at gmail.com> > >>>>> on Tue, 4 Apr 2017 15:29:40 -0500 writes: > > > I've done some more investigation into the problem, and it is very > > difficult to pin down. What it looks like is

Hey all, what is wrong with this command: system2("echo", env = c(VAR = "Hello World"), args = c("$VAR")) I am a bit confused, as help("system2") writes about the env option: > character vector of name=value strings to set environment variables. Is this option buggy, or am I using it just wrong? Thanks for your help Henning

On Tue, Mar 19, 2019 at 9:59 AM peter dalgaard <pdalgd at gmail.com> wrote: [...] > What you need is something like (NB: single quotes!) > > system2("sh", env = c("VAR='Hello World'"), args = c("-c 'echo $VAR'")) > Hello World Just out of curiosity, do you think it is possible to make this portable, assuming sh is available? On

>>>>> Michael Lawrence <lawrence.michael at gene.com> >>>>> on Mon, 26 Jan 2015 05:12:55 -0800 writes: > A isNamespaceLoaded() function would be a useful thing to > have in general if we are interested in readable code. An > efficient implementation would be just a bonus. Good point (readability), and thank you for the support! Note

> > >> I've done some more investigation into the problem, and it is very difficult to pin down. What it looks like is happening is roughly like this: - `p` is an environment and `p$e` is also an environment. - There is a loop. In each iteration, it looks for one item in `p$e`, saves it in a variable `x`, then removes that item from `p$e`. Then it invokes `x()`. The loop runs

I have two questions about the CRAN machines that build binary packages for Mac. When a new version of a package is released, (A) Do the downstream dependencies get re-checked? (B) Do the downstream dependencies get re-built? I have heard (but do not know for sure) that the answer to (A) is no, the downstream dependencies do not get rechecked. >From publicly available information on the

According to ?system2, I should be able to direct the output of STDERR to a file by giving the filename as a character vector to the "stderr" argument. But here is what happens. Given a ruby script test.rb (with its executable bit set): #!/usr/bin/env ruby STDOUT.puts "stdout" STDERR.puts "stderr" And the following R code: > t <- tempfile() > res <-

If an environment x contains a locked binding y which is also an environment, and then you try to assign a value to a binding inside of y, it can either succeed or fail, depending on how you refer to environment y. x <- new.env() x$y <- new.env() lockEnvironment(x, bindings = TRUE) # This assignment fails x$y$z <- 1 # Error in x$y$z <- 1 : cannot change value of locked binding for

Hi again! While investigating the bug report [*] I found out that on unix, system2 does not quote its `stdin` argument while preparing the command line to launch. It does shQuote the `stdout` and `stderr` arguments, and also the `f <- tmpfile()` variable (which is used if `input` argument is provided), which seems to set a precedent. On Windows, stdin, stdout, and stderr are handled

Is there any way to capture output (both stdout and stderr) from install.packages? Solutions like sink and capture.output don't work because the install.packages calls out to system2 which is executed in a separate process: test <- capture.output(install.packages("MASS")) The system2 function does have arguments stdout and stderr but afaik these cannot be controlled via

Hi all, I found some strange behaviour, which I think is a bug. Could someone make an account for me on Bugzilla or pass on my report? The problem: When pressing Ctrl-C when a file is sourced in R, run from Terminal (macOS), sometimes the entire session is ended right away, while I just want to stop the script. This is the case when I press Ctrl-C while some functions are running that don?t

I hope it's not too specific in my setup... I've tried with system2 added on the first line, so: Example.R: system2('ls', timeout=5) cat('Start non-interruptable functions\n') sample_a <- sample(1:1e7) sample_b <- sample(1:2e7) matching <- match(sample_a, sample_b) cat('Finished\n') Sys.sleep(10) And in terminal/bash: R --vanilla

According to the manual, the `stdout` argument of the `system2` function can redirect output to a file. This seems to work on unix, however I can't get it to work on windows. The toy example below, no `out.txt` or `err.txt` files are created. I tried sending it to an existing file, or expand the full file path, but with no success: setwd(tempdir()) system2("whoami",

I'm getting an R CMD check warning with a package (call it package A) that defines an S3 method but not the generic. The generic is defined in another package (package B). Package A imports the S3 generic from B. And there's one additional detail: the generic overrides a function in the stats package. I've created a minimal test package which reproduces the problem: