Alex Rivera | Logout

Library/package development - message when loading

Asked 2010-02-03T13:55:22.707
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is there any way to display a message when a user loads library(myCustomLibrary)? Upon loading, I want to display a message that tells the user how to run all the test functions.

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Quick points (and updated edit in 2021):

  • while if your package has a NAMESPACE, then .onLoad() is where you used to do this: but .onLoad() has been required to be 'silent'

  • if your package has a NAMESPACE, then .onAttach() is where can call, preferably via packageStartupMessage() (which can be suppressed where cat() or message() cannot

  • if your package does not have NAMESPACE, then you must add one now (and .First.lib() was where you used to do this) -- NAMESPACES have been mandatory for a few years now

  • either way, use packageStartupMessage() instead of cat() so that users have a choice of suppressing this.

answered 2010-02-03T14:38:48.883

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