Ns mutex - Revision history

Josephbui at 20:12, 21 June 2006

2006-06-21T20:12:37Z

71.214.77.117: fix url to documentation

2005-12-27T19:43:52Z

fix url to documentation

64.236.208.25 at 12:45, 7 October 2005

2005-10-07T12:45:27Z

WikiSysop: imported from WiKit id 605

2004-07-20T00:45:43Z

imported from WiKit id 605

New page

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

----

'''NAME'''

: ns_mutex - Operate on mutexes

'''SYNOPSIS'''

: '''ns_mutex''' ''option ?arg arg ...?''

'''DESCRIPTION'''

: This command provides a mechanism to manipulate mutexes. The legal ''option''s (which may be abbreviated) are:
* '''ns_mutex create'''

: Initializes a new mutual exclusion (mutex) lock and returns a handle to it.
* '''ns_mutex destroy''' ''object''

: Destroys the mutex and frees any resources it was using.

: '''NOTE:''' The mutex must be unlocked, or else the behavior is undefined and will likely crash the server. Before using this, you should probably look at [[Implementing a Mutex Pool]] instead.
* '''ns_mutex lock''' ''object''

: Attempt to acquire the mutex lock and block if it is already locked.
* '''ns_mutex unlock''' ''object''

: Release a previously acquired mutex lock.

'''EXAMPLES'''

'''SEE ALSO'''

: [[ns_cond]], [[ns_critsec]], [[ns_event]], [[ns_thread]]

----

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

← Older revision		Revision as of 20:12, 21 June 2006
Line 30:		Line 30:

	'''EXAMPLES'''		'''EXAMPLES'''
		+
		+	It seems like the only difference between ns_mutex lock and ns_critsec enter is that a thread can block itself by calling ns_mutex lock twice on one lock without calling ns_mutex unlock on that lock. Is there some reason to use ns_mutex instead of ns_critsec?
		+
		+	nsv_set . special_file_mutex [ns_mutex create]
		+
		+	proc write_special_file {data} {
		+	set mutex [nsv_get . special_file_mutex]
		+	ns_mutex lock $mutex
		+	set handle [open special_file w]
		+	puts $handle $data
		+	ns_mutex unlock $mutex
		+	}
		+
		+	proc read_special_file {data} {
		+	set mutex [nsv_get . special_file_mutex]
		+	ns_mutex lock $mutex
		+	set handle [open special_file r]
		+	set result [read $handle]
		+	ns_mutex unlock $mutex
		+	return $result
		+	}
		+
		+	proc change_special_file {data} {
		+	set mutex [nsv_get . special_file_mutex]
		+	# PROC WAITS FOREVER HERE
		+	ns_mutex lock $mutex
		+	set result [read_special_file]
		+	write_special_file $data
		+	ns_mutex unlock $mutex
		+	return $result
		+	}

	'''SEE ALSO'''		'''SEE ALSO'''

← Older revision		Revision as of 19:43, 27 December 2005
Line 1:		Line 1:
−	Man page: http://aolserver.com/docs/tcl/~~ns_mutex~~.html	+	Man page: http://www.aolserver.com/docs/devel/tcl/api/thread.html#ns_mutex

	----		----

@@ Line 14: / Line 14: @@
 : This command provides a mechanism to manipulate mutexes.  The legal ''option''s (which may be abbreviated) are:
-* '''ns_mutex create'''
+* '''ns_mutex create''' ''?name?''
-: Initializes a new mutual exclusion (mutex) lock and returns a handle to it.
+: Initializes a new mutual exclusion (mutex) lock and returns a handle to it.  If ''name'' is provided the mutex name will be set to this value.
 * '''ns_mutex destroy''' ''object''