Ns critsec - Revision history

Hcd000 at 15:39, 29 August 2008

2008-08-29T15:39:55Z

Josephbui: Added multiple sequential calls to ns_critsec enter to the example

2006-06-21T20:09:08Z

Added multiple sequential calls to ns_critsec enter to the example

Josephbui: Added an example

2006-06-21T19:54:06Z

Added an example

WikiSysop: imported from WiKit id 543

2004-06-15T19:04:36Z

imported from WiKit id 543

New page

Man page: http://aolserver.com/docs/tcl/ns_critsec.html

----

'''NAME'''

: ns_critsec - Operate on critical section objects

'''SYNOPSIS'''

: '''ns_critsec''' ''option ?arg arg ...?''

'''DESCRIPTION'''

: This command provides a mechanism to manipulate critical section objects. The legal ''option''s (which may be abbreviated) are:
* '''ns_critsec create'''

: Initializes a new critical section object and returns a handle to it.
* '''ns_critsec destroy''' ''object''

: Destroys the critical section object and frees any resources it was using.
* '''ns_critsec enter''' ''object''

: Enters the critical section. The thread will block if another thread is already in the critical section.
* '''ns_critsec leaves''' ''object''

: Leaves the critical section. When the thread leaves the critical section as many times as it has entered, a notification will be sent to other threads that are waiting on the critical section.

'''EXAMPLES'''

# need an example here

'''SEE ALSO'''

: [[ns_cond]], [[ns_event]], [[ns_mutex]], [[ns_thread]]

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[[Category Documentation]] - [[Category Core Tcl API]]

@@ Line 31: / Line 31: @@
 Is this the right way to use this command? The example is contrived, but I wanted to call ns_critsec multiple times.
-     # If a thread is executing either of these procs, no other
+     # If a thread is executing any of these procs, no other
-     # thread can execute any of these procs until first first
+     # thread can execute any of these procs until the first
      # thread has completely finished.
@@ Line 38: / Line 38: @@
      proc write_special_file {data} {
-         ns_critsec enter [nsv_get . special_file_critsec]
+         set critsec [nsv_get . special_file_critsec]
          set handle [open special_file w]
          puts $handle $data
          close $handle
-         ns_critsec leave [nsv_get . special_file_critsec]
+         ns_critsec leave $critsec
+     }
      proc read_special_file {} {
-         ns_critsec enter [nsv_get . special_file_critsec]
+         set critsec [nsv_get . special_file_critsec]
          set handle [open special_file r]
          set result [read $handle]
          close $handle
-         ns_critsec leave [nsv_get . special_file_critsec]
+         ns_critsec leave $critsec
          return $result
+     }

@@ Line 23: / Line 23: @@
 : Enters the critical section.  The thread will block if another thread is already in the critical section.
-* '''ns_critsec leaves''' ''object''
+* '''ns_critsec leave''' ''object''
 : Leaves the critical section.  When the thread leaves the critical section as many times as it has entered, a notification will be sent to other threads that are waiting on the critical section.

@@ Line 29: / Line 29: @@
 '''EXAMPLES'''
-     # need an example here
+Is this the right way to use this command? The example is contrived, but I wanted to call ns_critsec multiple times.
 '''SEE ALSO'''