The lock statement acquires the mutual-exclusion lock for a given object, executes a statement block, and then releases the lock. While a lock is held, the thread that holds the lock can again acquire and release the lock. Any other thread is blocked from acquiring the lock and waits until the lock is released. The lock statement ensures that a single thread has exclusive access to that object.
When you synchronize thread access to a shared resource, lock on a dedicated object instance (for example, private readonly object balanceLock = new object();) or another instance that is unlikely to be used as a lock object by unrelated parts of the code. Avoid using the same lock object instance for different shared resources, as it might result in deadlock or lock contention. In particular, avoid using the following types as lock objects:
The following example defines an Account class that synchronizes access to its private balance field by locking on a dedicated balanceLock instance. Using the same instance for locking ensures that the balance field can't be updated simultaneously by two threads attempting to call the Debit or Credit methods simultaneously.
Mark As Lost locks your screen with a passcode and lets you display a custom message with your phone number to help you get it back. You can also remotely erase your device if needed. Your custom message continues to display even after the device is erased.
lock (third-person singular simple present locks, present participle locking, simple past locked, past participle locked or (obsolete) locken)
Pair the Navis Paddle with any August Smart Lock for 100% hands-free, keyless entry. Arrive at your door with auto-unlock and easily push your door open with your hip or elbow when your hands are tied.
In economics, vendor lock-in, also known as proprietary lock-in or customer lock-in, makes a customer dependent on a vendor for products, unable to use another vendor without substantial switching costs.
The use of open standards and alternative options makes systems tolerant of change, so that decisions can be postponed until more information is available or unforeseen events are addressed. Vendor lock-in does the opposite: it makes it difficult to move from one solution to another.
This class of lock-in is potentially technologically hard to overcome if the monopoly is held up by barriers to market that are nontrivial to circumvent, such as patents, secrecy, cryptography or other technical hindrances.
Technology lock-in, as defined, is strictly of the collective kind. However, the personal variant is also a possible permutation of the variations shown in the table, but with no monopoly and no collectivity, it would be expected to be the weakest lock-in. Equivalent personal examples:
Microsoft's application software also exhibits lock-in through the use of proprietary file formats. Microsoft Outlook uses a proprietary, publicly undocumented datastore format. Present versions of Microsoft Word have introduced a new format MS-OOXML. This may make it easier for competitors to write documents compatible with Microsoft Office in the future by reducing lock-in. Microsoft released full descriptions of the file formats for earlier versions of Word, Excel and PowerPoint in February 2008.
Prior to March 2009, digital music files with digital rights management were available for purchase from the iTunes Store, encoded in a proprietary derivative of the AAC format that used Apple's FairPlay DRM system. These files are compatible only with Apple's iTunes media player software on Macs and Windows, their iPod portable digital music players, iPhone smartphones, iPad tablet computers, and the Motorola ROKR E1 and SLVR mobile phones. As a result, that music was locked into this ecosystem and available for portable use only through the purchase of one of the above devices, or by burning to CD and optionally re-ripping to a DRM-free format such as MP3 or WAV.
In January, 2005, an iPod purchaser named Thomas Slattery filed a suit against Apple for the \"unlawful bundling\" of their iTunes Music Store and iPod device. He stated in his brief: \"Apple has turned an open and interactive standard into an artifice that prevents consumers from using the portable hard drive digital music player of their choice.\" At the time Apple was stated to have an 80% market share of digital music sales and a 90% share of sales of new music players, which he claimed allowed Apple to horizontally leverage its dominant positions in both markets to lock consumers into its complementary offerings. In September 2005, U.S. District Judge James Ware approved Slattery v. Apple Computer Inc. to proceed with monopoly charges against Apple in violation of the Sherman Antitrust Act.
On June 7, 2006, the Norwegian Consumer Council stated that Apple's iTunes Music Store violates Norwegian law. The contract conditions were vague and \"clearly unbalanced to disfavor the customer\". The retroactive changes to the DRM conditions and the incompatibility with other music players are the major points of concern. In an earlier letter to Apple, consumer ombudsman Bjørn Erik Thon complained that iTunes' DRM mechanism was a lock-in to Apple's music players, and argued that this was a conflict with consumer rights that he doubted would be defendable by Norwegian copyright law.
As of 29 May 2007[update], tracks on the EMI label became available in a DRM-free format called iTunes Plus. These files are unprotected and are encoded in the AAC format at 256 kilobits per second, twice the bitrate of standard tracks bought through the service. iTunes accounts can be set to display either standard or iTunes Plus formats for tracks where both formats exist. These files can be used with any player that supports the AAC file format and are not locked to Apple hardware. They can be converted to MP format if desired[clarification needed].
Secure .gov websites use HTTPSA lock ( A locked padlock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.
Self Lock is the unique feature that lets you protect your identity in E-Verify and Self Check by placing a \"lock\" in E-Verify on your Social Security number (SSN). This helps prevent anyone else from using your SSN for an E-Verify case. If an employer enters your locked SSN in E-Verify to confirm employment authorization, it will result in an E-Verify Tentative Nonconfirmation (mismatch). With Self Lock, you are always in control - you can unlock your SSN any time a new employer needs to confirm your employment authorization in E-Verify. Your Self Lock remains active as long as your account remains valid, and you have not unlocked your SSN. The Self Lock feature is only available to myE-Verify account holders.
To lock your SSN, you must select and answer three challenge questions. Select questions you can easily answer, because you will need to answer them again to verify your identity if you receive an E-Verify Tentative Nonconfirmation (mismatch) due to Self Lock.
If lock is called by a thread that already owns the mutex, the behavior is undefined: for example, the program may deadlock. An implementation that can detect the invalid usage is encouraged to throw a std::system_error with error condition resource_deadlock_would_occur instead of deadlocking.
Throws std::system_error when errors occur, including errors from the underlying operating system that would prevent lock from meeting its specifications. The mutex is not locked in the case of any exception being thrown.
The Addalock is a portable door lock that can be easily installed and removed in seconds on almost any hinged door that opens inwards giving you added privacy once you are locked behind it. Addalock can be installed on the front door or any other doors of your home where you require that additional privacy. The Addalock is an ideal travel lock that you can use on your hotel/motel or rental unit and ideal for students away at college. The Addalock is made from chrome plated carbon steel and together with its unique shape makes it adjustable to almost any door thickness. Each Addalock comes with a travel pouch.
I travel to many countries for work and have to stay in hotels. Many people I work with have reported waking up with someone standing in their room in the middle of the night or when they get out of the shower. I bought my Adalock almost a year ago and have been able to use it on every hotel door, except one. I always carry this and a wedge it for hotel door security. It has worked in four countries, including the US. As far as it being difficult to remove, you need to practice with it so that you feel confident that you could remove it in an emergency. I can remove it in the dark in less than two seconds.
An Event object manages an internal flag that can be set to truewith the set() method and reset to false with theclear() method. The wait() method blocks until theflag is set to true. The flag is set to false initially.
A semaphore manages an internal counter which is decremented by eachacquire() call and incremented by each release() call.The counter can never go below zero; when acquire() findsthat it is zero, it blocks, waiting until some task callsrelease().
A barrier is a simple synchronization primitive that allows to block untilparties number of tasks are waiting on it.Tasks can wait on the wait() method and would be blocked untilthe specified number of tasks end up waiting on wait().At that point all of the waiting tasks would unblock simultaneously.
LOCK TABLE obtains a table-level lock, waiting if necessary for any conflicting locks to be released. If NOWAIT is specified, LOCK TABLE does not wait to acquire the desired lock: if it cannot be acquired immediately, the command is aborted and an error is emitted. Once obtained, the lock is held for the remainder of the current transaction. (There is no UNLOCK TABLE command; locks are always released at transaction end.) 59ce067264