The "Writing R Extensions" manual says that "R CMD check" can be
customized "by setting environment variables _R_CHECK_*_:, as
described in" the Tools section of the "R Internals" manual. 'R CMD check' was tested with R 3.0.1 under Fedora 18 Linux and with
Rtools 3.0 from April 16, 2013 under Windows 7. With the '--as-cran'
option, 7 matches were found; without it, only 3 were found. These
numbers were unaffected by the presence or absence of the '--timings'
parameter. On this basis, the default value of n_R_CHECK4CRAN was set
at 5.
1. x. <- Sys.getenv()
2. Fix CRAN_pattern
and n_R_CHECK4CRAN
if missing.
3. Let i be the indices of x. whose names match all the patterns in
the vector x.
4. Assume this is CRAN if length(i) >= n_R_CHECK4CRAN