What is the exec function in php?

I recently wrote svnmanager in php, but I found that all the exec functions in it are not executed, and there are no error prompts. I have not found a proper answer on the Internet for a long time, just write an exec test program? Phpexec (mkdirc: test, $ out); echo ($ out); echo, let alone I do not write anything ;? The output result is array.

I recently wrote svnmanager in php, but I found that all the exec functions in it are not executed, and there are no error prompts. I have not found a proper answer on the Internet for a long time, just write an exec test program? Php exec ("mkdir c:/test", $ out); echo ($ out); echo "don't say I do not write anything ";? The output result is "array.

I recently wrote svnmanager in php, but I found that all the exec functions in it are not executed, and there are no error prompts. I have not found a proper answer on the Internet for a long time, just write an exec test program.
Exec ("mkdir c:/test", $ out );
Echo ($ out );
Echo "let alone I do not write anything ";
?>
The output result is "array, let alone I do not write anything", instead of creating a test folder on drive C. The environment used is php5 and apache2. How can I modify or configure it.
It has been bothering me for a long time. I hope the prawns will not be enlightened ....

But in svnmanager, there are indeed such statements, and they are also very helpful. I don't know why it is difficult to make it on my machine.

Few people put php on a windows server to run it. Some functions in php only support linux. Not all functions can be used on windows!

Tile is easy to use. Is it a question of slashes... you know, thank you.

To run exec in IIS + PHP, you must first grant the permission to the php‑reader .exe(the permission must be added to the security section of cmd.exe). Otherwise, an error will occur.

Apache does not know what permissions are used for running, and does not know whether it is a permission issue.
I don't know why mkdir c:/test doesn't work. It means I'm happy to execute the exec function. In addition, the exec prototype is exec (string command, $ ar, $ status) if the value of status is 1, the program is not running. If the value is 0, the program runs successfully.

I know. There is no space in the path. Otherwise, the error "c:/program" is not a program or batch processing error. If you want to see this post, you can understand it.

I found that many external commands cannot be executed (because they are all installed as root). The result of running whoami is nobody. How can I run this command as a root user ?? Modify the configuration file php. ini to open the exec execution permission!

In this example, You need to optimize the time that each access occupies the database link.
0.1 seconds and 0.01 seconds are completely different.
In addition, consider the consumption of creating links. If the concurrency reaches a certain level, consider the connection pool.

I don't know what your requirements are, but it's a little scary if you have a few hundred simultaneous accesses.
For other methods, What Is memcached or something.
Shared Memory, daemon, and Operation locks may be helpful to you, but it is costly to develop it on your own.
Database links are bottlenecks. However, using a connection pool to reduce the time needed for each link can still meet your needs. However, it is unrealistic to have tens of thousands of links per second.
Memory tables are much faster than normal tables (data updates and some situations that cannot be cached), shortening the connection time and slowing down when no normal tables are not cached, it will make your application more stable and efficient.
Memory tables, I am using a direct table.
Modified. I don't know what will happen during the next peak period.
There is still a large error in statistics, zzzzz ~~~~.


The current solution is to send an online identity request every 50 seconds on the webpage. This request will allow the database to update the last response time of the user.

Then, an offline request is sent every five minutes to clear the session table.

The request sending code is written in Ajax on the page where the SWF game is located.
If 1000 users send this message at the same time, I am worried about sending the message once every 50 seconds.

Because it is sent once every five minutes, the PHP file will first check whether the minute date ("I") in the creation time of a txt file is consistent with the current time. If it is consistent, nothing will be done, if they are inconsistent, re-write the file and execute the command. This means that the server only processes the file once every one minute.

But that 50-second request is a little scary .... Every 50 seconds, each online user has an update statement ....
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