Signals in R Programming Language

Here’s the translation of the Go code to R, formatted in Markdown suitable for Hugo:

Our example demonstrates how to handle signals in R. This can be useful for gracefully shutting down a program or stopping input processing when it receives certain signals.

library(parallel)

# Create a function to handle the signal
handle_signal <- function(sig) {
  cat("\n")
  cat(sig, "\n")
  stopCluster(cl)
  quit(save = "no")
}

# Register the signal handlers
tools::pskill(Sys.getpid(), tools::SIGINT)
tools::pskill(Sys.getpid(), tools::SIGTERM)

# Create a cluster for parallel processing
cl <- makeCluster(1)

# Start the main process
cat("awaiting signal\n")

# Use tryCatch to handle the signals
tryCatch({
  while(TRUE) {
    Sys.sleep(1)
  }
},
interrupt = function(e) {
  handle_signal("interrupt")
},
error = function(e) {
  handle_signal("terminated")
})

In this R script:

1. We use the parallel library to create a cluster, which is somewhat analogous to creating a goroutine in the original example.

2. We define a handle_signal function that prints the signal received and performs cleanup operations.

3. We register signal handlers for SIGINT and SIGTERM using tools::pskill.

4. We create a cluster using makeCluster, which will be used to demonstrate cleanup on program termination.

5. The main part of the program is an infinite loop inside a tryCatch block. This allows us to catch and handle the signals.

6. When a signal is received, the appropriate handler is called, which prints the signal type, stops the cluster, and exits the program.

To run this program:

Rscript signals.R

The program will block, waiting for a signal. By pressing Ctrl+C (which the terminal shows as ^C), we can send a SIGINT signal, causing the program to print “interrupt” and then exit.

$ Rscript signals.R
awaiting signal
^C
interrupt

This example demonstrates how to handle signals in R, allowing for graceful shutdown or interruption of long-running processes.