message                 package:base                 R Documentation

Diagnostic Messages

Description:

     Generate a diagnostic message from its arguments.

Usage:

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

     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.

appendLF: logical: should messages given as a character string have a
          newline appended?

    expr: expression to evaluate.

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())

