Using Rtools40 on Windows

As of version 4.0 (April 2020) R for Windows uses a brand new toolchain bundle called Rtools40.

This version of Rtools upgrades the mingw-w64 gcc toolchains to 8.3.0, and also introduces a new build system based on msys2, which makes easier to build and maintain R itself as well as system libraries needed by R packages on Windows. For more information about this, see the links in the bottom of this document.

Older versions of Rtools: This document talks about Rtools40, the current version used for R-4.0 and up. For previous versions of Rtools (used up till R 3.6), please see this page.

Installing Rtools40

Note that you only need rtools40 if you want to build R packages which contain C/C++/Fortran code. By default, R for Windows installs the precompiled "binary packages" from CRAN, for which you do not need rtools!

To use rtools40, download the installer from CRAN:

• On Windows 64-bit: rtools40-x86_64.exe (recommended: includes both i386 and x64 compilers)
• On Windows 32-bit: rtools40-i686.exe (i386 compilers only)

After the installation is completed, you need to perform one more step to be able to compile R packages: you need to put the location of the rtools make utilities (bash, make, etc) on the PATH. The easiest way to do so is create a text file .Renviron in your Documents folder which contains the following line:

PATH="${RTOOLS40_HOME}\usr\bin;${PATH}"

You can do this with a text editor, or you can even do it from R like so:

# Automatically put Rtools on the PATH
writeLines('PATH="${RTOOLS40_HOME}\\usr\\bin;${PATH}"', con = "~/.Renviron")

Now restart R and verify that make can be found, which should show the path to your rtools installation. If this works you can try to install an R package from source:

# Confirm that make.exe is on the PATH
Sys.which("make")
## "C:\\rtools40\\usr\\bin\\make.exe"

# Try to install a package
install.packages("jsonlite", type = "source")

If this succeeds, you're good! See the links below to learn more about rtools40 and the Windows build infrastructure.

Additional Resources

Documentation about rtools40 for R users and package authors:

• rtools40: some info about the new rtools build system
• faq: common issues with Rtools40 and R on Windows.

Other resources with information about building R and system libraries:

• r-base: Scripts for building R for Windows using Rtools40.
• rtools-packages: Toolchains and static libraries for Rtools 4.0 (GCC 8+)
• rtools-backports: Backported C/C++ libraries for the gcc-4.9.3 legacy toolchain (for R 3.3 - 3.6)
• rtools-installer: Builds the Rtools40 installer bundle.