You probably want with_makevars() instead of this function.

set_makevars(
  variables,
  old_path = makevars_user(),
  new_path = tempfile(),
  assignment = c("=", ":=", "?=", "+=")
)

Arguments

variables

[named character]
new variables and their values

old_path

[character(1)]
location of existing Makevars file to modify.

new_path

[character(1)]
location of the new Makevars file

assignment

[character(1)]
assignment type to use.

Details

Unlike with_makevars(), it does not activate the new Makevars file, i.e. it does not set the R_MAKEVARS_USER environment variable.