R/onAttach.R

In fstcore: R Bindings to the 'Fstlib' Library

#  fstcore - R bindings to the fstlib library
#
#  Copyright (C) 2017-present, Mark AJ Klik
#
#  This file is part of the fstcore R package.
#
#  This Source Code Form is subject to the terms of the Mozilla Public
#  License, v. 2.0. If a copy of the MPL was not distributed with this file,
#  You can obtain one at https://mozilla.org/MPL/2.0/.
#
#  https://www.mozilla.org/en-US/MPL/2.0/FAQ/
#
#  You can contact the author at:
#  - fstcore R package source repository : https://github.com/fstpackage/fstcore


.onAttach <- function(libname, pkgname) {  # nolint
  # Runs when attached to search() path such as by library() or require()
  if (interactive()) {
    v <- packageVersion("fstcore")
    d <- read.dcf(system.file("DESCRIPTION", package = "fstcore"), fields = c("Packaged", "Built"))

    if (is.na(d[1])) {
      if (is.na(d[2])) {
        return() # neither field exists
      } else {
        d <- unlist(strsplit(d[2], split = "; "))[3]
      }
    } else {
      d <- d[1]
    }

    # version number odd => dev
    dev <- as.integer(v[1, 3]) %% 2 == 1

    packageStartupMessage("fstcore package v", v, if (dev) paste0(" IN DEVELOPMENT built ", d))

    # check for old version
    if (dev && (Sys.Date() - as.Date(d)) > 28)
      packageStartupMessage("\n!!! This development version of the package is rather old, please update !!!")

    # option fst_threads can be used to set the number of threads when the package is loaded.
    fst_threads_option <- getOption("fst_threads")
    nr_of_threads <- getnrofthreads()

    if (!is.null(fst_threads_option) && (!is.numeric(fst_threads_option) || is.na(fst_threads_option))) {
      # report incorrect thread option
      packageStartupMessage("Incorrect option 'fst_threads' found and ignored.")
    }

    # check for OpenMP support
    if (!hasopenmp()) {
      packageStartupMessage("(OpenMP was not detected, using single threaded mode)")
    } else if (!is.null(fst_threads_option) && nr_of_threads == fst_threads_option) {

      # the number of threads is equal to the amount specified in option fst_threads
        packageStartupMessage("(OpenMP detected, using ", nr_of_threads, " threads from option 'fst_threads')")
    } else {
      # number of threads set to default or selected by the user after loading
      packageStartupMessage("(OpenMP detected, using ", nr_of_threads, " threads)")
    }
  }
}