ps() Attributes Vector

 psAttributes.names <- c("thread id",
                         "elapsed time",
                         "cpu time",
                         "input",
                         "output",
                         "error"
                         "command",
                         "frames",
                         "toplevel"
                        )
 psAttributes <-  2^(c((1:length(psAttributes.names))-1))
 names(psAttributes) <- psAttributes.names

 ps(attributes=c("thread id", "frames"))

 if(is(attributes,"character"))
  val = sum(psAttributes[attributes])
 else if(is(attributes,"numeric")) {
   # check the values agains those in psAttributes
  if(any(is.na(match(attributes,psAttributes))))
    stop("incorrect values passed as attributes to ps")
   val = sum(attributes)
 }

thread id

the thread name used internally and by which the thread can be referenced. This is also the value in the thread object's name slot.

elapsed time

the length of time since the creation of the thread

cpu time

the length of time for the evaluation of this thread

input

the input connection for this thread, typically NULL.

output

the output connection for this thread

error

the error connection for this thread on which warnings and errors are printed.

command

the current command or if this is too difficult, the command that constituted the first task for this thread.

frames

session frames and/or databases associated with this thread. Each thread will have at least one of these databases for its own use.

toplevel

the identifier of the database to which toplevel assignments in this frame are committed.