| warnings {base} | R Documentation | 
warnings prints the top-level variable last.warning in a
pleasing form.
warnings(...)
... | 
arguments to be passed to cat. | 
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