R: Diagnostic Messages

message {base} | R Documentation

## Diagnostic Messages

### Description

Generate a diagnostic message from its arguments.

### Usage

    message(..., domain = NULL, appendLF = TRUE)
    suppressMessages(expr, classes = "message")

    packageStartupMessage(..., domain = NULL, appendLF = TRUE)
    suppressPackageStartupMessages(expr)

    .makeMessage(..., domain = NULL, appendLF = FALSE)

### Arguments

`...` | zero or more objects which can be coerced to character (and which are pasted together with no separator) or (for `message` only) a single condition object.
`domain` | see `gettext`. If `NA`, messages will not be translated, see also the note in `stop`.
`appendLF` | logical: should messages given as a character string have a newline appended?
`expr` | expression to evaluate.
`classes` | character, indicating which classes of messages should be suppressed.

### Details

`message` is used for generating ‘simple’ diagnostic messages which are neither warnings nor errors, but nevertheless represented as conditions. Unlike warnings and errors, a final newline is regarded as part of the message, and is optional. The default handler sends the message to the `stderr()` connection.

If a condition object is supplied to `message` it should be the only argument, and further arguments will be ignored, with a warning.

While the message is being processed, a `muffleMessage` restart is available.

`suppressMessages` evaluates its expression in a context that ignores all ‘simple’ diagnostic messages.

`packageStartupMessage` is a variant whose messages can be suppressed separately by `suppressPackageStartupMessages`. (They are still messages, so can be suppressed by `suppressMessages`.)

`.makeMessage` is a utility used by `message`, `warning` and `stop` to generate a text message from the `...` arguments by possible translation (see `gettext`) and concatenation (with no separator).

### See Also

`warning` and `stop` for generating warnings and errors; `conditions` for condition handling and recovery.

`gettext` for the mechanisms for the automated translation of text.

### Examples

    message("ABC", "DEF")
    suppressMessages(message("ABC"))

    testit <- function() {
      message("testing package startup messages")
      packageStartupMessage("initializing ...", appendLF = FALSE)
      Sys.sleep(1)
      packageStartupMessage(" done")
    }

    testit()
    suppressPackageStartupMessages(testit())
    suppressMessages(testit())

[Package base version 4.0.5 Index]