Minimal example of royxgen2 issue

roxygen_test.R

#' The length of a string (in characters).
#'
#' @param string input character vector
#' @return numeric vector giving number of characters in each element of the
#'   character vector.  Missing strings have missing length.
#' @seealso \code{\link{nchar}} which this function wraps
#' @export
#' @examples
#' str_length(letters)
#' str_length(c("i", "like", "programming", NA))
str_length <- function(string) {
  string <- check_string(string)
  
  nc <- nchar(string, allowNA = TRUE)
  is.na(nc) <- is.na(string)
  nc
}


> roxygen2::roxygenise(".")
First time using roxygen2 4.0. Upgrading automatically...
Writing NAMESPACE
Warning messages:
1: @title [test.R#1]: unknown tag 
2: @description [test.R#1]: unknown tag 
3: @param [test.R#4]: unknown tag 
4: @return [test.R#5]: unknown tag 
5: @seealso [test.R#7]: unknown tag 
6: @export [test.R#8]: unknown tag 
7: @examples [test.R#9]: unknown tag 

@kevinushey see below as well as this issue

sessionInfo()
R version 3.1.3 (2015-03-09)
Platform: x86_64-apple-darwin13.4.0 (64-bit)
Running under: OS X 10.11 (unknown)

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] stats graphics grDevices utils datasets methods base

other attached packages:
[1] httr_1.0.0 raster_2.3-40 sp_1.1-0 ggplot2_1.0.1 roxygen2_5.0.0

loaded via a namespace (and not attached):
[1] colorspace_1.2-6 digest_0.6.8 grid_3.1.3 gtable_0.1.2 lattice_0.20-31
[6] magrittr_1.5 MASS_7.3-40 munsell_0.4.2 plyr_1.8.2 proto_0.3-10
[11] R6_2.0.1 Rcpp_0.11.6 reshape2_1.4.1 scales_0.3.0 stringi_0.4-1
[16] stringr_1.0.0 tools_3.1.3