Parse the fopen () function in php and use the open file mode description _ PHP

This article provides a detailed analysis of the fopen () function in php using the open file mode description. For more information, see The fopen () function is used to open a file in PHP.
The first parameter of this function contains the name of the file to be opened, and the second parameter specifies the mode used to open the file:
The code is as follows:
$ File = fopen ("welcome.txt", "r ");
?>

The file may be opened in the following mode:
R: Read-only. The pointer is located at the beginning of the file. if the file is not reported.
R +: read/write. The pointer is located at the beginning of the file. if the file is not stored, an error is returned.
W: write only. Open and clear the file content. if the file does not exist, create a new file.
W +: read/write. Open and clear the file content. if the file does not exist, create a new file.
A: append. Open the file and locate the pointer at the end of the file. if the file does not exist, create a new file.
A +: Read/append. Open the file and locate the pointer at the end of the file. if the file does not exist, create a new file.
X: Write-only. Create a new file. If the object already exists, FALSE is returned.
X +: read/write. Create a new file. If the file already exists, FALSE and an error are returned.