PHP Programming About include once and include

There is a lot of search on the Internet about this problem.,Include and include once are not much research.,The difference is that include is whether you have introduced the file before.,It's still introduced.,include once checks whether the file has been introduced before.,If there is, it's no longer introduced.。

If the file introduced by Incloude is sent incorrectly or the file does not exist, Include issues a warning and continues with the program, while Require generates a fatal error and terminates the program.

The require once() statement includes and runs the specified file during script execution. This behavior is similar to the require() statement, except that if ** in the file is already included, it will not be included again. The require once() function does almost the same thing as require().

The include once() statement includes and runs the specified file during script execution. This behavior is similar to the include() statement, except that if ** in the file is already included, it will not be included again. As the name of this statement suggests, it will only be included once.

The clude once() function does almost the same thing as include().

The purpose of require once is to check whether the file has been loaded before, if it is not loaded, it will be loaded, and if it has been loaded, it will not be loaded again. For example, if a file defines a type, if you get an error when you load the file twice, require once will avoid the error.

include If two files are introduced, both with the same function name, then a redefinition error will occur. This error can be avoided by using include once, which is generally used more often. The difference between include and once should be required according to the actual situation.

The difference between include and require.

When the file to be included does not exist, include generates a warning, and the program following the statement will continue to execute; Require results in a fatal error and the program terminates.

include once and require once should be used in cases where the same file may be included more than once during script execution, and you want to make sure that it is only included once to avoid function redefinitions, variable reassignments, etc.

Loaded when used, this function is typically placed in the process section of the process control.

Loaded at the beginning, this function is usually placed at the top of the php program.

3.The once suffix indicates that the loaded ones are not loaded.

It's basically the same.,It seems to use more require once.。

The nclude statement takes all the text tags present in the specified file and copies them to the file that uses the include statement.

Syntax: The require statement has the same function as the include statement, but it is different in terms of error handling.

require generates a fatal error (e compile error) and stops the script.

include only generates a warning (e warning) and the script continues.

Include and run the specified file, and the include() function type, except that if the ** in the file is already included, it will not be included again. As the name of this statement suggests, it will only be included once.

The include once (php 4, php 5) include once statement contains and runs the specified file during script execution. This behavior is similar to the include statement, except that if the file has already been included, it will not be included again. As the name of this statement suggests, it will only be included once.

include once can be used in cases where the same file may be included more than once during script execution, and you want to make sure that it is only included once to avoid function redefinitions, variable reassignments, etc.