Detailed explanation of the differences and usage of PHP versions

When we install PHP modules, we sometimes need to pay attention to the compiled version of PHP. The following is a detailed explanation of the differences and usage of VC6, VC9, TS, and NTS versions in PHP, and introduces the two execution methods of PHP.

1. The difference between VC6 and VC9:
The VC6 version is compiled using the Visual Studio 6 compiler. If your PHP is installed with Apache, then you should choose the VC6 version.

The VC9 version is compiled using the Visual Studio 2008 compiler. If your PHP is set up using IIS, then you should choose the VC9 version.

The VC9 version is for the IIS server and does not support APACHE, while the VC6 version provides support for both IIS and Apache

2. The difference between Ts and nts:
The Windows version of PHP has Thread Safe and NoneThread Safe starting from version 5.2.1.

First understand from the literal meaning, Thread Safe is thread safety, and thread (Thread) safety check will be performed during execution to prevent CGI execution from starting new threads when there are new requirements and exhausting system resources. Non Thread Safe is non-thread safe and does not perform thread (Thread) safety checks during execution.

3. There are two execution methods of PHP: ISAPI and FastCGI.
ISAPI execution method is used in the form of a DLL dynamic library, which can be executed after being requested by the user. It will not disappear immediately after processing a user request, so thread safety checks are required to improve the execution efficiency of the program, so if ISAPI is used to execute PHP, and it is recommended to choose the ThreadSafe version;

The FastCGI execution method uses a single thread to perform operations, so there is no need to perform thread safety checks. Removing the protection of thread safety checks can improve execution efficiency, so if FastCGI is used to execute PHP. It is recommended to choose the NonThread Safe version. Check the Thread Safety item through phpinfo();. This item is to check whether it is thread safe. If it is: enabled, generally speaking it should be the ts version, otherwise it is the nts version.