bionic (3) ns_thread.3aolserver.gz

NAME

       ns_thread - commands

SYNOPSIS

       ns_thread begin script

       ns_thread begindetached script

       ns_thread get

       ns_thread getid

       ns_thread wait tid

       ns_thread yield

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DESCRIPTION

       ns_thread begin:
              begins  a  new  thread which evaluates the specified script and then exits. It returns a thread ID
              that must eventually be passed to ns_thread wait. (Failing to call ns_thread wait will  eventually
              result in no new threads being created.)

       ns_thread begindetached:
              begins a detached thread that doesn't have to be (and can't be) waited for.

       ns_thread get:
              gets  the  thread  ID  of  the  current  thread.  The  result is a thread ID that can be passed to
              ns_thread wait and may look something like "tid532".

       ns_thread getid:
              gets the thread integer number for the current thread. The result is  a  small  integer  used  for
              identifying threads is a human-readable way, such as "1" or "1120", for example.

       ns_thread wait:
              waits  for  the  specified  thread  to exit. The tid argument is a thread ID returned by ns_thread
              begin or ns_thread get.

       ns_thread yield:
              causes the current thread to yield.

EXAMPLES

       This example is similar to the example under the ns_sockselect function of connecting to the  10  servers
       and  waiting  to  service them with the ns_sockselect command. In this case, though, each connection gets
       it's own thread.

       # This is the procedure which is evaluated for each thread and # handles  a  single  connection  to  host
       number $i

       proc getpage {i} {
           global pages
           # new thread will start here - first connect to host
           set host [format "www%2d.foo.com" $i]
           set fds [ns_sockopen $host 80
           set r [lindex $fds 0]
           set w [lindex $fds 1]
           # next, send request            0r"
           puts $w "GET /index.htm HTTP/1.0
           flush $w
           # then read page
           set pages($i) [read $r]
           # and close sockets
           close $w
           close $r
           # thread goes away here and other threads waiting
           # on ns_thread wait will wakeup }

       # Here's the loop which creates the threads which run getpage.  for {set i 1} {$i < 9} {incr i} {
           set tids($i) [ns_thread begin "getpage $i"] }

       # wait for the threads to exit and then process the pages for {set i 1} {$i < 9} {incr i} {
           ns_thread wait $tids($i)
           # output page
           ... process the page in $pages($i) put there by other thread ...  }

       Note  that  the code here is much simpler to follow than the ns_sockselect example; that's the benefit of
       multithreaded programming. However, it uses more resources as threads need to be created and initialized.
       This can be a problem if you plan to create many threads.

SEE ALSO

KEYWORDS

       threads