The R Project SVN R

\name{warning}
\title{Warning Messages}
\usage{
warning(message)
}
\alias{warning}
\arguments{
\item{message}{character string (of length 1) or \code{NULL}.}
}
\description{
\code{warning} generates a warning message that corresponds to its
argument and the expression or function from which it was called.
}
\details{
The result \bold{depends} on the value of
\code{\link{options}("warn")}.
If \code{warn} is negative warnings are ignored; if it is zero they
are stored and printed after the top--level function has completed;
if it is one they are printed as they occur and if it is 2 (or larger)
warnings are turned into errors.

If \code{warn} is zero (the default),
a top--level variable \code{last.warning} is
created.  It contains the warnings which can be printed via a call to
\code{\link{warnings}}.
}
\seealso{\code{\link{stop}} for fatal errors, \code{\link{warnings}},
    and \code{\link{options}(warn=..)}.
}
\examples{
\testonly{eigenval <- 10 ^ -rnorm(1,m=6)
if(eigenval < 1.e-7) warning("system near singular")}
}
\keyword{programming}