warning {base} | R Documentation |
Generates a warning message that corresponds to its argument(s) and (optionally) the expression or function from which it was called.
warning(..., call. = TRUE, immediate. = FALSE, domain = NULL)
suppressWarnings(expr)
... |
zero or more objects which can be coerced to character (and which are pasted together with no separator) or a single condition object. |
call. |
logical, indicating if the call should become part of the warning message. |
immediate. |
logical, indicating if the call should be output
immediately, even if |
expr |
expression to evaluate. |
domain |
see |
The result depends on the value of
options("warn")
and on handlers established in the
executing code.
If a condition object is supplied it should be the only argument, and further arguments will be ignored, with a message.
warning
signals a warning condition by (effectively) calling
signalCondition
. If there are no handlers or if all handlers
return, then the value of warn = getOption("warn")
is
used to determine the appropriate action. If 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. Calling warning(immediate. = TRUE)
turns warn <=
0
into warn = 1
for this call only.
If warn
is zero (the default), a read-only variable
last.warning
is created. It contains the warnings which can be
printed via a call to warnings
.
Warnings will be truncated to getOption("warning.length")
characters, default 1000, indicated by [... truncated]
.
While the warning is being processed, a muffleWarning
restart
is available. If this restart is invoked with invokeRestart
,
then warning
returns immediately.
An attempt is made to coerce other types of inputs to warning
to character vectors.
suppressWarnings
evaluates its expression in a context that
ignores all warnings.
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
stop
for fatal errors,
message
for diagnostic messages,
warnings
,
and options
with argument warn=
.
gettext
for the mechanisms for the automated translation
of messages.
testit <- function() warning("testit")
testit() ## shows call
testit <- function() warning("problem in testit", call. = FALSE)
testit() ## no call
suppressWarnings(warning("testit"))