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1. • Yes

     • In short: yes. There are four conditions, known as the Coffman conditions, that are necessary for a deadlock to occur. Remove any one of these, and a deadlock can’t happen: Mutual exclusion. There’s a resource that only one entity can use at a time. Hold and wait. An entity is holding one resource while waiting for another. No preemption.
     devblogs.microsoft.com › pfxteam › are-deadlocks-still-possible-with-await

     Are deadlocks still possible with await? - .NET Parallel ...

2. Top results related to are deadlocks still possible with await in php

   • Are private constants possible in PHP?

     Top Answer

     Answered Apr 19, 2012 · 44 votes

     The answer is a simple "no". PHP doesn't support this concept. The best you can do is a private static variable in the class, which isn't as good of course because it's not readonly. But you just have to work around it.

     Edit

     Your question got me thinking - here's something I've never tried, but might work. Put another way "this is untested". But say you wanted a "private constant" called FOO:

     // "Constant" definitionsprivate function __get($constName){ // Null for non-defined "constants" $val = null;- switch($constName){ case 'FOO': $val = 'MY CONSTANT UNCHANGEABLE VALUE'; break; case 'BAR': $val = 'MY OTHER CONSTANT VALUE'; break; }- return $val;}-

     Of course your syntax would look a bit odd:

     // Retrieve the "constant"$foo = $this->FOO;-

     ...but at least this wouldn't work:

     $this->FOO = 'illegal!';-

     Maybe something worth trying?

     Cheers

     Check all answers on Stack Overflow

     1/5

   • In PHP, how to match id with names which names are in another table

     Top Answer

     Answered Jun 29, 2016 · 0 votes

     The best solution would be to normalise your url_category_block table and store each policy_id - category id pair in its own record. In this case a simple join on the field values will do the trick you are asking.

     The quick solution is to use find_in_set() function to join the 2 tables:

     select *from url_category_block ainner join url_category_data b on find_in_set(b.id, a.category_list)>0

     Check all answers on Stack Overflow

     2/5

   • In PHP, how to print a number with 2 decimals, but only if there are decimals already?

     Top Answer

     Answered Apr 13, 2011 · 10 votes

     This is simple and it will also let you tweak the format to taste:

     $var = sprintf($var == intval($var) ? "%d" : "%.2f", $var);-

     It will format the variable as an integer (%d) if it has no decimals, and with exactly two decimal digits (%.2f) if it has a decimal part.

     See it in action.

     Update: As Archimedix points out, this will result in displaying 3.00 if the input value is in the range (2.995, 3.005). Here's an improved check that fixes this:

     $var = sprintf(round($var, 2) == intval($var) ? "%d" : "%.2f", $var);-

     Check all answers on Stack Overflow

     3/5

   • Are there any potential issues with using `if(count($_POST) > 0)` to check if any data has been POSTed in PHP?

     Top Answer

     Answered Dec 07, 2012 · 1 votes

     This would be the simplest way to determine if one or more values have been sent via POST.

     if ($_POST) { // it is 100% reliably implied that count($_POST) > 0}-

     However, sometimes you may receive a form post that doesn't contain any keys/values. An example would be an "accept our terms of service by clicking the checkbox" type form, where the only form field is a checkbox, or submit button. Checkbox name/value pairs are only sent if the checkbox gets checked, and submit buttons name/values aren't always sent by browsers. Another example where $_POST could have no entries could be a file upload form. A good form handler will properly behave in these scenarios. You can use the following to detect a post request in ALL circumstances.

     if ($_SERVER['REQUEST_METHOD'] === 'POST') { // its a post request, although we may have 0 posted values}-

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     4/5

   • Are semicolons in PHP optional?

     Top Answer

     Answered Oct 11, 2018 · 14 votes

     In general, I would always recommend including the semi-colon, but you're right, it can be dropped in this instance.

     You may only drop the semi-colon after a statement when the statement is followed immediately by a closing PHP tag -- ie ?>.

     This is documented in the PHP documentation here: http://php.net/manual/en/language.basic-syntax.instruction-separation.php

     This is a feature from the earliest days of the language, aimed at making templated code slightly easier to read.

     Unlike Javascript, there are no other circumstances where dropping the semi-colon is permitted.

     Check all answers on Stack Overflow

     5/5

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3. People also ask

   Does async/await make deadlocks more likely?

   • Don’t let this deadlock discussion scare you. Using async/await doesn’t make deadlocks any more likely than they were before; you still need the same conditions you always previously needed in order to end up with these kinds of situations. In fact, there are often mitigating factors when using async/await that make deadlocks less likely.

   Are deadlocks still possible with await? | .NET Parallel

   devblogs.microsoft.com/pfxteam/are-deadlocks-still-possible-with-await/

   See all results for this question

   What causes a deadlock in async/wait?

   • The Async/Await FAQ goes into detail on exactly when contexts are captured and used for continuations. This kind of deadlock is always the result of mixing synchronous with asynchronous code. Usually this is because people are just trying out async with one small piece of code and use synchronous code everywhere else.

   Don't Block on Async Code - Stephen Cleary

   blog.stephencleary.com/2012/07/dont-block-on-async-code.html

   See all results for this question

   Can a deadlock happen if you remove a Coffman condition?

   • In short: yes. There are four conditions, known as the Coffman conditions, that are necessary for a deadlock to occur. Remove any one of these, and a deadlock can’t happen: Mutual exclusion . There’s a resource that only one entity can use at a time. Hold and wait. An entity is holding one resource while waiting for another. No preemption .

   Are deadlocks still possible with await? | .NET Parallel

   devblogs.microsoft.com/pfxteam/are-deadlocks-still-possible-with-await/

   See all results for this question

   What causes a deadlock in Windows 10?

   • This type of deadlock can be caused for either “context”. There are two best practices (both covered in my intro post) that avoid this situation: In your “library” async methods, use ConfigureAwait (false) wherever possible. Don’t block on Tasks; use async all the way down. Consider the first best practice.

   Don't Block on Async Code - Stephen Cleary

   blog.stephencleary.com/2012/07/dont-block-on-async-code.html

   See all results for this question

4. stackoverflow.com › questions › 36343488php - Proper way of handling and preventing deadlocks - Stack ...

   stackoverflow.com › questions › 36343488

   • Cached

   Apr 1, 2016 · This may lead to a dead lock if 1 gets A, then 2 gets B, then 1 waits for B and 2 waits for A - indefinitely. The solution is, thankfully quite simple: anytime if a process needs to lock two or more resources, it must do so in a "sorted" fashion.

5. devblogs.microsoft.com › pfxteam › are-deadlocksAre deadlocks still possible with await? - .NET Parallel ...

   devblogs.microsoft.com › pfxteam › are-deadlocks

   • Cached

   Apr 12, 2012 · In short: yes. There are four conditions, known as the Coffman conditions, that are necessary for a deadlock to occur. Remove any one of these, and a deadlock can’t happen: Mutual exclusion . There’s a resource that only one entity can use at a time. Hold and wait. An entity is holding one resource while waiting for another. No preemption .

6. blog.stephencleary.com › 2012 › 07Don't Block on Async Code - Stephen Cleary

   blog.stephencleary.com › 2012 › 07

   • Cached

   Dec 1, 2014 · This code will also deadlock. For the same reason. What Causes the Deadlock. Here’s the situation: remember from my intro post that after you await a Task, when the method continues it will continue in a context. In the first case, this context is a UI context (which applies to any UI except Console applications). In the second case, this ...

7. www.mullie.eu › parallel-processing-multi-tasking-phpAsync processing or multitasking in PHP · Matthias Mullie

   www.mullie.eu › parallel-processing-multi-tasking-php

   • Cached

   Jun 19, 2013 · Not properly accounted for, this can lead to unexpected results like race conditions or deadlocks. In PHP however, this will not be the case: memory is not shared, though it is still possible to affect data in another thread. pthreads. PHP Docs. The only multithreading solution in PHP is the pthreads extension.

8. dev.mysql.com › doc › refmanMySQL :: MySQL 8.0 Reference Manual :: 17.7.5 Deadlocks in InnoDB

   dev.mysql.com › doc › refman

   • Cached

   FOR UPDATE and UPDATE ... WHERE statements. The possibility of deadlocks is not affected by the isolation level, because the isolation level changes the behavior of read operations, while deadlocks occur because of write operations.

9. www.sitepoint.com › community › tHow do you deal with database transaction deadlocks in PHP ...

   www.sitepoint.com › community › t

   • Cached

   Dec 7, 2012 · PHP. Lemon_Juice December 7, 2012, 10:33am 1. More and more often I come across a problem of deadlocks in mysql. I like to enclose portions of SQL updates, inserts and deletes in a transaction...

10. dba.stackexchange.com › questions › 6910innodb - Preventing mysql deadlocks in your php application ...

    dba.stackexchange.com › questions › 6910

    • Cached

    This is done in order to "lock out" those selected rows from other session's writing/deleting actions (but other sessions can still read the rows) until your transaction completes. From that point, the rows that were locked with the SELECT LOCK IN SHARE MODE statement are released so other sessions can access them for writing, deleting, etc.