warnings: Print Warning Messages
In robertzk/monadicbase: The R Base Package

Description Usage Arguments Details Value Warning References See Also Examples

warnings and its print method print the variable last.warning in a pleasing form.

1	warnings(...)

...

arguments to be passed to cat.

See the description of options("warn") for the circumstances under which there is a last.warning object and warnings() is used. In essence this is if options(warn = 0) and warning has been called at least once.

It is possible that last.warning refers to the last recorded warning and not to the last warning, for example if options(warn) has been changed or if a catastrophic error occurred.

an object of S3 class "warnings", basically a named list.

It is undocumented where last.warning is stored nor that it is visible, and this is subject to change.

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

warning.

## NB this example is intended to be pasted in,
##    rather than run by example()
ow <- options("warn")
for(w in -1:1) {
   options(warn = w); cat("\n warn =", w, "\n")
   for(i in 1:3) { cat(i,"..\n"); m <- matrix(1:7, 3,4) }
}
warnings()
options(ow) # reset
tail(warnings(), 2) # see the last two warnings only (via '[' method)