Start the Dynamic HTML Help System
This function starts the internal help server, so that HTML help pages are rendered when requested.
startDynamicHelp(start = TRUE)
- logical: whether to start or shut down the dynamic help
NA, the server is started if not already running.
This function starts the internal HTTP server, which runs on the
loopback interface (
is set to a vector of integer values,
startDynamicHelp will try
those ports in order; otherwise, it tries up to 10 random ports to
find one not in use. It can be disabled by setting the environment
variable R_DISABLE_HTTPD to a non-empty value.
startDynamicHelp is called by functions that need to use the
server, so would rarely be called directly by a user.
options(help_type = "html") must be set to actually
make use of HTML help, although it might be the default for an R
If the server cannot be started or is disabled,
help.start will be unavailable and requests for HTML
help will give text help (with a warning).
The browser in use does need to be able to connect to the loopback
interface: occasionally it is set to use a proxy for HTTP on all
interfaces, which will not work -- the solution is to add an exception
The chosen port number is returned invisibly (which will be
0if the server has been stopped).
Rd2HTML is used to render the package help pages.