Interact with the user to choose a CRAN mirror.
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Logical. If true, use a graphical list: on Windows or
the macOS GUI use a list box, and on a Unix-alike use a Tk widget if
package tcltk and an X server are available. Otherwise use a
Optional numeric value giving which entry to select.
Whether to prefer HTTPS mirrors.
Logical, get all known mirrors or only the ones flagged as OK.
Logical, try to get most recent list from the CRAN master or use file on local disk only.
A list of mirrors is stored in file ‘R_HOME/doc/CRAN_mirrors.csv’, but first an on-line list of current mirrors is consulted, and the file copy used only if the on-line list is inaccessible.
This function is called by a Windows GUI menu item and by
contrib.url if it finds the initial dummy value of
useHTTPS argument defaults to
useHTTPS = TRUE, HTTPS mirrors will be offered in preference to
HTTP mirrors (which are listed in a sub-menu). If it is set to
FALSE, no HTTPS mirrors will be offered. Choosing an HTTPS
mirror provides some guarantees on the identity of the site chosen and
so is recommended. (However, most but not all R builds support
downloading from HTTPS sites.)
ind chooses a row in the list of current mirrors, by number. It
is best used with
local.only = TRUE and row numbers in
chooseCRANmirror(), this function is invoked for its
side effect of updating
getCRANmirrors() returns a data frame with mirror information.