Does PHP have threading

Question

I found this PECL package called threads  but there is not a release yet  And nothing is coming up on the PHP website

User · Answer

I have a PHP threading class that s been running flawlessly in a production environment for over two years now   EDIT  This is now available as a composer library and as part of my MVC framework  Hazaar MVC   See  https   git hazaarlabs com hazaar hazaar-thread

User · Answer

You can use pcntl fork   to achieve something similar to threads  Technically it s separate processes  so the communication between the two is not as simple with threads  and I believe it will not work if PHP is called by apache

User · Answer

There is a Threading extension being activley developed based on PThreads that looks very promising at https   github com krakjoe pthreads

User · Answer

From the PHP manual for the pthreads extension      pthreads is an Object Orientated API that allows user-land multi-threading in PHP  It includes all the tools you need to create multi-threaded applications targeted at the Web or the Console  PHP applications can create  read  write  execute and synchronize with Threads  Workers and Stackables    As unbelievable as this sounds  it s entirely true  Today  PHP can multi-thread for those wishing to try it   The first release of PHP4  22 May 2000  PHP was shipped with a thread safe architecture - a way for it to execute multiple instances of it s interpreter in separate threads in multi-threaded SAPI   Server API   environments  Over the last 13 years  the design of this architecture has been maintained and advanced  It has been in production use on the worlds largest websites ever since   Threading in user land was never a concern for the PHP team  and it remains as such today  You should understand that in the world where PHP does it s business  there s already a defined method of scaling - add hardware  Over the many years PHP has existed  hardware has got cheaper and cheaper and so this became less and less of a concern for the PHP team  While it was getting cheaper  it also got much more powerful  today  our mobile phones and tablets have dual and quad core architectures and plenty of RAM to go with it  our desktops and servers commonly have 8 or 16 cores  16 and 32 gigabytes of RAM  though we may not always be able to have two within budget and having two desktops is rarely useful for most of us   Additionally  PHP was written for the non-programmer  it is many hobbyists native tongue  The reason PHP is so easily adopted is because it is an easy language to learn and write   The reason PHP is so reliable today is because of the vast amount of work that goes into it s design  and every single decision made by the PHP group  It s reliability and sheer greatness keep it in the spot light  after all these years  where it s rivals have fallen to time or pressure    Multi-threaded programming is not easy for most  even with the most coherent and reliable API  there are different things to think about  and many misconceptions  The PHP group do not wish for user land multi-threading to be a core feature  it has never been given serious attention - and rightly so  PHP should not be complex  for everyone   All things considered  there are still benefits to be had from allowing PHP to utilize it s production ready and tested features to allow a means of making the most out of what we have  when adding more isn t always an option  and for a lot of tasks is never really needed   pthreads achieves  for those wishing to explore it  an API that does allow a user to multi-thread PHP applications  It s API is very much a work in progress  and designated a beta level of stability and completeness   It is common knowledge that some of the libraries PHP uses are not thread safe  it should be clear to the programmer that pthreads cannot change this  and does not attempt to try  However  any library that is thread safe is useable  as in any other thread safe setup of the interpreter   pthreads utilizes Posix Threads   even in Windows    what the programmer creates are real threads of execution  but for those threads to be useful  they must be aware of PHP - able to execute user code  share variables and allow a useful means of communication   synchronization    So every thread is created with an instance of the interpreter  but by design  it s interpreter is isolated from all other instances of the interpreter - just like  multi-threaded Server API environments  pthreads attempts to bridge the gap in a sane and safe way  Many of the concerns of the programmer of threads in C just aren t there for the programmer of pthreads  by design  pthreads is copy on read and copy on write   RAM is cheap    so no two instances ever manipulate the same physical data  but they can both affect data in another thread  The fact that PHP may use thread unsafe features in it s core programming is entirely irrelevant  user threads  and it s operations are completely safe   Why copy on read and copy on write   public function run                  1   this- gt data    data               2   this- gt other   someOperation  this- gt data               3  echo preg match  pattern   replace   thread- gt data      1  While a read  and write lock are held on the pthreads object data store  data is copied from its original location in memory to the object store  pthreads does not adjust the refcount of the variable  Zend is able to free the original data if there are no further references to it    2  The argument to someOperation references the object store  the original data stored  which it itself a copy of the result of  1   is copied again for the engine into a zval container  while this occurs a read lock is held on the object store  the lock is released and the engine can execute the function  When the zval is created  it has a refcount of 0  enabling the engine to free the copy on completion of the operation  because no other references to it exist    3  The last argument to preg match references the data store  a read lock is obtained  the data set in  1  is copied to a zval  again with a refcount of 0  The lock is released  The call to preg match operates on a copy of data  that is itself a copy of the original data   Things to know    The object store s hash table where data is stored  thread safe  is based on the TsHashTable shipped with PHP  by Zend  The object store has a read and write lock  an additional access lock is provided for the  TsHashTable such that if requires   and it does  var dump print r  direct access to properties as the PHP engine wants to reference them   pthreads can manipulate the TsHashTable outside of the defined API  The locks are only held while the copying operations occur  when the copies have been made the locks are released  in a sensible order    This means    When a write occurs  not only are a read and write lock held  but an additional access lock  The table itself is locked down  there is no possible way another context can lock  read  write or affect it  When a read occurs  not only is the read lock held  but the additional access lock too  again the table is locked down    No two contexts can physically nor concurrently access the same data from the object store  but writes made in any context with a reference will affect the data read in any context with a reference   This is shared nothing architecture and the only way to exist is co-exist  Those a bit savvy will see that  there s a lot of copying going on here  and they will wonder if that is a good thing  Quite a lot of copying goes on within a dynamic runtime  that s the dynamics of a dynamic language  pthreads is implemented at the level of the object  because good control can be gained over one object  but methods - the code the programmer executes - have another context  free of locking and copies - the local method scope  The object scope in the case of a pthreads object should be treated as a way to share data among contexts  that is it s purpose  With this in mind you can adopt techniques to avoid locking the object store unless it s necessary  such as passing local scope variables to other methods in a threaded object rather than having them copy from the object store upon execution   Most of the libraries and extensions available for PHP are thin wrappers around 3rd parties  PHP core functionality to a degree is the same thing  pthreads is not a thin wrapper around Posix Threads  it is a threading API based on Posix Threads  There is no point in implementing Threads in PHP that it s users do not understand or cannot use  There s no reason that a person with no knowledge of what a mutex is or does should not be able to take advantage of all that they have  both in terms of skill  and resources  An object functions like an object  but wherever two contexts would otherwise collide  pthreads provides stability and safety    Anyone who has worked in java will see the similarities between a pthreads object and threading in java  those same people will have no doubt seen an error called ConcurrentModificationException - as it sounds an error raised by the java runtime if two threads write the same physical data concurrently  I understand why it exists  but it baffles me that with resources as cheap as they are  coupled with the fact the runtime is able to detect the concurrency at the exact and only time that safety could be achieved for the user  that it chooses to throw a possibly fatal error at runtime rather than manage the execution and access to the data   No such stupid errors will be emitted by pthreads  the API is written to make threading as stable  and compatible as is possible  I believe   Multi-threading isn t like using a new database  close attention should be paid to every word in the manual and examples shipped with pthreads   Lastly  from the PHP manual      pthreads was  and is  an experiment with pretty good results  Any of its limitations or features may change at any time  that is the nature of experimentation  It s limitations - often imposed by the implementation - exist for good reason  the aim of pthreads is to provide a useable solution to multi-tasking in PHP at any level  In the environment which pthreads executes  some restrictions and limitations are necessary in order to provide a stable environment

User · Answer

Here is an example of what Wilco suggested    cmd    nohup nice -n 10  usr bin php -c  path to php ini -f  path to php file php action generate var1 id 23 var2 id 35 gen id 535  gt   path to log file log  amp  echo       pid   shell exec  cmd     Basically this executes the PHP script at the command line  but immediately returns the PID and then runs in the background   The echo    ensures nothing else is returned other than the PID   This allows your PHP script to continue or quit if you want  When I have used this  I have redirected the user to another page  where every 5 to 60 seconds an AJAX call is made to check if the report is still running   I have a table to store the gen id and the user it s related to   The check script runs the following   exec  ps      pid    processState   if  count  processState   lt  2            less than 2 rows in the ps  therefore report is complete     There is a short post on this technique here  http   nsaunders wordpress com 2007 01 12 running-a-background-process-in-php

User · Answer

Here is an example of what Wilco suggested    cmd    nohup nice -n 10  usr bin php -c  path to php ini -f  path to php file php action generate var1 id 23 var2 id 35 gen id 535  gt   path to log file log  amp  echo       pid   shell exec  cmd     Basically this executes the PHP script at the command line  but immediately returns the PID and then runs in the background   The echo    ensures nothing else is returned other than the PID   This allows your PHP script to continue or quit if you want  When I have used this  I have redirected the user to another page  where every 5 to 60 seconds an AJAX call is made to check if the report is still running   I have a table to store the gen id and the user it s related to   The check script runs the following   exec  ps      pid    processState   if  count  processState   lt  2            less than 2 rows in the ps  therefore report is complete     There is a short post on this technique here  http   nsaunders wordpress com 2007 01 12 running-a-background-process-in-php

User · Answer

There is the rather obscure  and soon to be deprecated  feature called ticks  The only thing I have ever used it for  is to allow a script to capture SIGKILL  Ctrl C  and close down gracefully

User · Answer

Ever heard about appserver from techdivision   It is written in php and works as a appserver managing multithreads for high traffic php applications  Is still in beta but very promesing

User · Answer

I know this is a way old question  but you could look at http   phpthreadlib sourceforge net   Bi-directional communication  support for Win32  and no extensions required

User · Answer

You can use pcntl fork   to achieve something similar to threads  Technically it s separate processes  so the communication between the two is not as simple with threads  and I believe it will not work if PHP is called by apache

User · Answer

There is a Threading extension being activley developed based on PThreads that looks very promising at https   github com krakjoe pthreads

User · Answer

There is nothing available that I m aware of  The next best thing would be to simply have one script execute another via CLI  but that s a bit rudimentary  Depending on what you are trying to do and how complex it is  this may or may not be an option

User · Answer

In short  yes  there is multithreading in php but you should use multiprocessing instead   Backgroud info  threads vs  processes  There is always a bit confusion about the distinction of threads and processes  so i ll shortly describe both    A thread is a sequence of commands that the CPU will process  The only data it consists of is a program counter  Each CPU core will only process one thread at a time but can switch between the execution of different ones via scheduling  A process is a set of shared resources  That means it consists of a part of memory  variables  object instances  file handles  mutexes  database connections and so on  Each process also contains one or more threads  All threads of the same process share its resources  so you may use a variable in one thread that you created in another  If those threads are parts of two different processes  then they cannot access each others resources directly  In this case you need inter-process communication through e g  pipes  files  sockets      Multiprocessing  You can achieve parallel computing by creating new processes  that also contain a new thread  with php  If your threads do not need much communication or synchronization  this is your choice  since the processes are isolated and cannot interfere with each other s work  Even if one crashes  that doesn t concern the others  If you do need much communication  you should read on at  multithreading  or - sadly - consider using another programming language  because inter-process communication and synchronization introduces a lot of complexion   In php you have two ways to create a new process   let the OS do it for you  you can tell your operation system to create a new process and run a new  or the same  php script in it    for linux you can use the following or consider Darryl Hein s answer    cmd    nice php script php 2 gt  amp 1  amp  echo      pclose popen  cmd   r      for windows you may use this    cmd    start  processname   MIN  belownormal cmd  c  script php 2 gt  amp 1    pclose popen  cmd   r        do it yourself with a fork  php also provides the possibility to use forking through the function pcntl fork    A good tutorial on how to do this can be found here but i strongly recommend not to use it  since fork is a crime against humanity and especially against oop   Multithreading  With multithreading all your threads share their resources so you can easily communicate between and synchronize them without a lot of overhead  On the other side you have to know what you are doing  since race conditions and deadlocks are easy to produce but very difficult to debug   Standard php does not provide any multithreading but there is an  experimental  extension that actually does - pthreads  Its api documentation even made it into php net  With it you can do some stuff as you can in real programming languages  -  like this   class MyThread extends Thread       public function run              do something time consuming           t   new MyThread    if  t- gt start         while  t- gt isRunning             echo              usleep 100              t- gt join        For linux there is an installation guide right here at stackoverflow s   For windows there is one now    First you need the thread-safe version of php  You need the pre-compiled versions of both pthreads and its php extension  They can be downloaded here  Make sure that you download the version that is compatible with your php version  Copy php pthreads dll  from the zip you just downloaded  into your php extension folder   phpDirectory  ext   Copy pthreadVC2 dll into  phpDirectory   the root folder - not the extension folder   Edit  phpDirectory  php ini and insert the following line  extension php pthreads dll  Test it with the script above with some sleep or something right there where the comment is    And now the big BUT  Although this really works  php wasn t originally made for multithreading  There exists a thread-safe version of php and as of v5 4 it seems to be nearly bug-free but using php in a multi-threaded environment is still discouraged in the php manual  but maybe they just did not update their manual on this  yet   A much bigger problem might be that a lot of common extensions are not thread-safe  So you might get threads with this php extension but the functions you re depending on are still not thread-safe so you will probably encounter race conditions  deadlocks and so on in code you did not write yourself

User · Answer

Just an update  its seem that PHP guys are working on supporting thread and its available now   Here is the link to it  http   php net manual en book pthreads php

User · Answer

If anyone cares  I have revived php threading  not the same as threads  but similar  and I actually have it to the point where it works  somewhat  well   Project page  Download  for Windows PHP 5 3 VC9 TS   Examples  README

User · Answer

Here is an example of what Wilco suggested    cmd    nohup nice -n 10  usr bin php -c  path to php ini -f  path to php file php action generate var1 id 23 var2 id 35 gen id 535  gt   path to log file log  amp  echo       pid   shell exec  cmd     Basically this executes the PHP script at the command line  but immediately returns the PID and then runs in the background   The echo    ensures nothing else is returned other than the PID   This allows your PHP script to continue or quit if you want  When I have used this  I have redirected the user to another page  where every 5 to 60 seconds an AJAX call is made to check if the report is still running   I have a table to store the gen id and the user it s related to   The check script runs the following   exec  ps      pid    processState   if  count  processState   lt  2            less than 2 rows in the ps  therefore report is complete     There is a short post on this technique here  http   nsaunders wordpress com 2007 01 12 running-a-background-process-in-php

User · Answer

I have a PHP threading class that s been running flawlessly in a production environment for over two years now   EDIT  This is now available as a composer library and as part of my MVC framework  Hazaar MVC   See  https   git hazaarlabs com hazaar hazaar-thread

User · Answer

I know this is a way old question  but you could look at http   phpthreadlib sourceforge net   Bi-directional communication  support for Win32  and no extensions required

User · Answer

You can use pcntl fork   to achieve something similar to threads  Technically it s separate processes  so the communication between the two is not as simple with threads  and I believe it will not work if PHP is called by apache

User · Answer

There is the rather obscure  and soon to be deprecated  feature called ticks  The only thing I have ever used it for  is to allow a script to capture SIGKILL  Ctrl C  and close down gracefully

User · Answer

pcntl fork   is what you are searching for  but its process forking not threading  so you will have the problem of data exchange  to solve them you can use phps semaphore functions   http   www php net manual de ref sem php   message queues may be a bit easier for the beginning than shared memory segments   Anyways  a strategy i am using in a web framework that i am developing which loads resource intensive blocks of a web page  probably with external requests  parallel  i am doing a job queue to know what data i am waiting for and then i fork off the jobs for every process  once done they store their data in the apc cache under a unique key the parent process can access  once every data is there it continues  i am using simple usleep   to wait because inter process communication is not possible in apache  children will loose the connection to their parents and become zombies      so this brings me to the last thing  its important to self kill every child   there are as well classes that fork processes but keep data  i didn t examine them but zend framework has one  and they usually do slow but reliably code  you can find it here  http   zendframework com manual 1 9 en zendx console process unix overview html i think they use shm segments  well last but not least there is an error on this zend website  minor mistake in the example   while   process1- gt isRunning    amp  amp   process2- gt isRunning          sleep 1     should of course be  while   process1- gt isRunning       process2- gt isRunning          sleep 1

User · Answer

Ever heard about appserver from techdivision   It is written in php and works as a appserver managing multithreads for high traffic php applications  Is still in beta but very promesing

User · Answer

There is the rather obscure  and soon to be deprecated  feature called ticks  The only thing I have ever used it for  is to allow a script to capture SIGKILL  Ctrl C  and close down gracefully

User · Answer

From the PHP manual for the pthreads extension      pthreads is an Object Orientated API that allows user-land multi-threading in PHP  It includes all the tools you need to create multi-threaded applications targeted at the Web or the Console  PHP applications can create  read  write  execute and synchronize with Threads  Workers and Stackables    As unbelievable as this sounds  it s entirely true  Today  PHP can multi-thread for those wishing to try it   The first release of PHP4  22 May 2000  PHP was shipped with a thread safe architecture - a way for it to execute multiple instances of it s interpreter in separate threads in multi-threaded SAPI   Server API   environments  Over the last 13 years  the design of this architecture has been maintained and advanced  It has been in production use on the worlds largest websites ever since   Threading in user land was never a concern for the PHP team  and it remains as such today  You should understand that in the world where PHP does it s business  there s already a defined method of scaling - add hardware  Over the many years PHP has existed  hardware has got cheaper and cheaper and so this became less and less of a concern for the PHP team  While it was getting cheaper  it also got much more powerful  today  our mobile phones and tablets have dual and quad core architectures and plenty of RAM to go with it  our desktops and servers commonly have 8 or 16 cores  16 and 32 gigabytes of RAM  though we may not always be able to have two within budget and having two desktops is rarely useful for most of us   Additionally  PHP was written for the non-programmer  it is many hobbyists native tongue  The reason PHP is so easily adopted is because it is an easy language to learn and write   The reason PHP is so reliable today is because of the vast amount of work that goes into it s design  and every single decision made by the PHP group  It s reliability and sheer greatness keep it in the spot light  after all these years  where it s rivals have fallen to time or pressure    Multi-threaded programming is not easy for most  even with the most coherent and reliable API  there are different things to think about  and many misconceptions  The PHP group do not wish for user land multi-threading to be a core feature  it has never been given serious attention - and rightly so  PHP should not be complex  for everyone   All things considered  there are still benefits to be had from allowing PHP to utilize it s production ready and tested features to allow a means of making the most out of what we have  when adding more isn t always an option  and for a lot of tasks is never really needed   pthreads achieves  for those wishing to explore it  an API that does allow a user to multi-thread PHP applications  It s API is very much a work in progress  and designated a beta level of stability and completeness   It is common knowledge that some of the libraries PHP uses are not thread safe  it should be clear to the programmer that pthreads cannot change this  and does not attempt to try  However  any library that is thread safe is useable  as in any other thread safe setup of the interpreter   pthreads utilizes Posix Threads   even in Windows    what the programmer creates are real threads of execution  but for those threads to be useful  they must be aware of PHP - able to execute user code  share variables and allow a useful means of communication   synchronization    So every thread is created with an instance of the interpreter  but by design  it s interpreter is isolated from all other instances of the interpreter - just like  multi-threaded Server API environments  pthreads attempts to bridge the gap in a sane and safe way  Many of the concerns of the programmer of threads in C just aren t there for the programmer of pthreads  by design  pthreads is copy on read and copy on write   RAM is cheap    so no two instances ever manipulate the same physical data  but they can both affect data in another thread  The fact that PHP may use thread unsafe features in it s core programming is entirely irrelevant  user threads  and it s operations are completely safe   Why copy on read and copy on write   public function run                  1   this- gt data    data               2   this- gt other   someOperation  this- gt data               3  echo preg match  pattern   replace   thread- gt data      1  While a read  and write lock are held on the pthreads object data store  data is copied from its original location in memory to the object store  pthreads does not adjust the refcount of the variable  Zend is able to free the original data if there are no further references to it    2  The argument to someOperation references the object store  the original data stored  which it itself a copy of the result of  1   is copied again for the engine into a zval container  while this occurs a read lock is held on the object store  the lock is released and the engine can execute the function  When the zval is created  it has a refcount of 0  enabling the engine to free the copy on completion of the operation  because no other references to it exist    3  The last argument to preg match references the data store  a read lock is obtained  the data set in  1  is copied to a zval  again with a refcount of 0  The lock is released  The call to preg match operates on a copy of data  that is itself a copy of the original data   Things to know    The object store s hash table where data is stored  thread safe  is based on the TsHashTable shipped with PHP  by Zend  The object store has a read and write lock  an additional access lock is provided for the  TsHashTable such that if requires   and it does  var dump print r  direct access to properties as the PHP engine wants to reference them   pthreads can manipulate the TsHashTable outside of the defined API  The locks are only held while the copying operations occur  when the copies have been made the locks are released  in a sensible order    This means    When a write occurs  not only are a read and write lock held  but an additional access lock  The table itself is locked down  there is no possible way another context can lock  read  write or affect it  When a read occurs  not only is the read lock held  but the additional access lock too  again the table is locked down    No two contexts can physically nor concurrently access the same data from the object store  but writes made in any context with a reference will affect the data read in any context with a reference   This is shared nothing architecture and the only way to exist is co-exist  Those a bit savvy will see that  there s a lot of copying going on here  and they will wonder if that is a good thing  Quite a lot of copying goes on within a dynamic runtime  that s the dynamics of a dynamic language  pthreads is implemented at the level of the object  because good control can be gained over one object  but methods - the code the programmer executes - have another context  free of locking and copies - the local method scope  The object scope in the case of a pthreads object should be treated as a way to share data among contexts  that is it s purpose  With this in mind you can adopt techniques to avoid locking the object store unless it s necessary  such as passing local scope variables to other methods in a threaded object rather than having them copy from the object store upon execution   Most of the libraries and extensions available for PHP are thin wrappers around 3rd parties  PHP core functionality to a degree is the same thing  pthreads is not a thin wrapper around Posix Threads  it is a threading API based on Posix Threads  There is no point in implementing Threads in PHP that it s users do not understand or cannot use  There s no reason that a person with no knowledge of what a mutex is or does should not be able to take advantage of all that they have  both in terms of skill  and resources  An object functions like an object  but wherever two contexts would otherwise collide  pthreads provides stability and safety    Anyone who has worked in java will see the similarities between a pthreads object and threading in java  those same people will have no doubt seen an error called ConcurrentModificationException - as it sounds an error raised by the java runtime if two threads write the same physical data concurrently  I understand why it exists  but it baffles me that with resources as cheap as they are  coupled with the fact the runtime is able to detect the concurrency at the exact and only time that safety could be achieved for the user  that it chooses to throw a possibly fatal error at runtime rather than manage the execution and access to the data   No such stupid errors will be emitted by pthreads  the API is written to make threading as stable  and compatible as is possible  I believe   Multi-threading isn t like using a new database  close attention should be paid to every word in the manual and examples shipped with pthreads   Lastly  from the PHP manual      pthreads was  and is  an experiment with pretty good results  Any of its limitations or features may change at any time  that is the nature of experimentation  It s limitations - often imposed by the implementation - exist for good reason  the aim of pthreads is to provide a useable solution to multi-tasking in PHP at any level  In the environment which pthreads executes  some restrictions and limitations are necessary in order to provide a stable environment

User · Answer

There is nothing available that I m aware of  The next best thing would be to simply have one script execute another via CLI  but that s a bit rudimentary  Depending on what you are trying to do and how complex it is  this may or may not be an option

User · Answer

Here is an example of what Wilco suggested    cmd    nohup nice -n 10  usr bin php -c  path to php ini -f  path to php file php action generate var1 id 23 var2 id 35 gen id 535  gt   path to log file log  amp  echo       pid   shell exec  cmd     Basically this executes the PHP script at the command line  but immediately returns the PID and then runs in the background   The echo    ensures nothing else is returned other than the PID   This allows your PHP script to continue or quit if you want  When I have used this  I have redirected the user to another page  where every 5 to 60 seconds an AJAX call is made to check if the report is still running   I have a table to store the gen id and the user it s related to   The check script runs the following   exec  ps      pid    processState   if  count  processState   lt  2            less than 2 rows in the ps  therefore report is complete     There is a short post on this technique here  http   nsaunders wordpress com 2007 01 12 running-a-background-process-in-php

User · Answer

There is nothing available that I m aware of  The next best thing would be to simply have one script execute another via CLI  but that s a bit rudimentary  Depending on what you are trying to do and how complex it is  this may or may not be an option

User · Answer

pcntl fork   is what you are searching for  but its process forking not threading  so you will have the problem of data exchange  to solve them you can use phps semaphore functions   http   www php net manual de ref sem php   message queues may be a bit easier for the beginning than shared memory segments   Anyways  a strategy i am using in a web framework that i am developing which loads resource intensive blocks of a web page  probably with external requests  parallel  i am doing a job queue to know what data i am waiting for and then i fork off the jobs for every process  once done they store their data in the apc cache under a unique key the parent process can access  once every data is there it continues  i am using simple usleep   to wait because inter process communication is not possible in apache  children will loose the connection to their parents and become zombies      so this brings me to the last thing  its important to self kill every child   there are as well classes that fork processes but keep data  i didn t examine them but zend framework has one  and they usually do slow but reliably code  you can find it here  http   zendframework com manual 1 9 en zendx console process unix overview html i think they use shm segments  well last but not least there is an error on this zend website  minor mistake in the example   while   process1- gt isRunning    amp  amp   process2- gt isRunning          sleep 1     should of course be  while   process1- gt isRunning       process2- gt isRunning          sleep 1

User · Answer

If anyone cares  I have revived php threading  not the same as threads  but similar  and I actually have it to the point where it works  somewhat  well   Project page  Download  for Windows PHP 5 3 VC9 TS   Examples  README

User · Answer

You can use pcntl fork   to achieve something similar to threads  Technically it s separate processes  so the communication between the two is not as simple with threads  and I believe it will not work if PHP is called by apache

User · Answer

There is nothing available that I m aware of  The next best thing would be to simply have one script execute another via CLI  but that s a bit rudimentary  Depending on what you are trying to do and how complex it is  this may or may not be an option

User · Answer

In short  yes  there is multithreading in php but you should use multiprocessing instead   Backgroud info  threads vs  processes  There is always a bit confusion about the distinction of threads and processes  so i ll shortly describe both    A thread is a sequence of commands that the CPU will process  The only data it consists of is a program counter  Each CPU core will only process one thread at a time but can switch between the execution of different ones via scheduling  A process is a set of shared resources  That means it consists of a part of memory  variables  object instances  file handles  mutexes  database connections and so on  Each process also contains one or more threads  All threads of the same process share its resources  so you may use a variable in one thread that you created in another  If those threads are parts of two different processes  then they cannot access each others resources directly  In this case you need inter-process communication through e g  pipes  files  sockets      Multiprocessing  You can achieve parallel computing by creating new processes  that also contain a new thread  with php  If your threads do not need much communication or synchronization  this is your choice  since the processes are isolated and cannot interfere with each other s work  Even if one crashes  that doesn t concern the others  If you do need much communication  you should read on at  multithreading  or - sadly - consider using another programming language  because inter-process communication and synchronization introduces a lot of complexion   In php you have two ways to create a new process   let the OS do it for you  you can tell your operation system to create a new process and run a new  or the same  php script in it    for linux you can use the following or consider Darryl Hein s answer    cmd    nice php script php 2 gt  amp 1  amp  echo      pclose popen  cmd   r      for windows you may use this    cmd    start  processname   MIN  belownormal cmd  c  script php 2 gt  amp 1    pclose popen  cmd   r        do it yourself with a fork  php also provides the possibility to use forking through the function pcntl fork    A good tutorial on how to do this can be found here but i strongly recommend not to use it  since fork is a crime against humanity and especially against oop   Multithreading  With multithreading all your threads share their resources so you can easily communicate between and synchronize them without a lot of overhead  On the other side you have to know what you are doing  since race conditions and deadlocks are easy to produce but very difficult to debug   Standard php does not provide any multithreading but there is an  experimental  extension that actually does - pthreads  Its api documentation even made it into php net  With it you can do some stuff as you can in real programming languages  -  like this   class MyThread extends Thread       public function run              do something time consuming           t   new MyThread    if  t- gt start         while  t- gt isRunning             echo              usleep 100              t- gt join        For linux there is an installation guide right here at stackoverflow s   For windows there is one now    First you need the thread-safe version of php  You need the pre-compiled versions of both pthreads and its php extension  They can be downloaded here  Make sure that you download the version that is compatible with your php version  Copy php pthreads dll  from the zip you just downloaded  into your php extension folder   phpDirectory  ext   Copy pthreadVC2 dll into  phpDirectory   the root folder - not the extension folder   Edit  phpDirectory  php ini and insert the following line  extension php pthreads dll  Test it with the script above with some sleep or something right there where the comment is    And now the big BUT  Although this really works  php wasn t originally made for multithreading  There exists a thread-safe version of php and as of v5 4 it seems to be nearly bug-free but using php in a multi-threaded environment is still discouraged in the php manual  but maybe they just did not update their manual on this  yet   A much bigger problem might be that a lot of common extensions are not thread-safe  So you might get threads with this php extension but the functions you re depending on are still not thread-safe so you will probably encounter race conditions  deadlocks and so on in code you did not write yourself

User · Answer

There is the rather obscure  and soon to be deprecated  feature called ticks  The only thing I have ever used it for  is to allow a script to capture SIGKILL  Ctrl C  and close down gracefully

User · Answer

Just an update  its seem that PHP guys are working on supporting thread and its available now   Here is the link to it  http   php net manual en book pthreads php

[php] Does PHP have threading?

Examples related to php

Examples related to multithreading

Examples related to apache

Examples related to command-line-interface