| % File src/library/tools/man/startDynamicHelp.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 2009-2015 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{startDynamicHelp} |
| \alias{startDynamicHelp} |
| \alias{help.ports} |
| \alias{R_DISABLE_HTTPD} |
| |
| \title{Start the Dynamic HTML Help System} |
| \description{ |
| This function starts the internal help server, so that HTML help pages |
| are rendered when requested. |
| } |
| \usage{ |
| startDynamicHelp(start = TRUE) |
| } |
| \arguments{ |
| \item{start}{logical: whether to start or shut down the dynamic help |
| system. If \code{NA}, the server is started if not already running.} |
| } |
| \details{ |
| This function starts the internal HTTP server, which runs on the |
| loopback interface (\code{127.0.0.1}). If \code{options("help.ports")} |
| is set to a vector of non-zero integer values, \code{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 \env{R_DISABLE_HTTPD} to a non-empty value or \code{options("help.ports")} |
| to \code{0}. |
| |
| \code{startDynamicHelp} is called by functions that need to use the |
| server, so would rarely be called directly by a user. |
| |
| Note that \code{options(help_type = "html")} must be set to actually |
| make use of HTML help, although it might be the default for an \R |
| installation. |
| |
| If the server cannot be started or is disabled, |
| \code{\link{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 |
| for \code{127.0.0.1}. |
| } |
| \value{ |
| The chosen port number is returned invisibly (which will be \code{0} |
| if the server has been stopped). |
| } |
| \seealso{ |
| \code{\link{help.start}} and \code{\link{help}(help_type = "html")} |
| will attempt to start the HTTP server if required |
| |
| \code{\link{Rd2HTML}} is used to render the package help pages. |
| } |
| \keyword{ documentation } |