What is the usage of the php readfile function?

The readfile function is used to read a file and output it to the browser. Its basic syntax is as follows:

readfile(filename)

The parameter filename represents the path of the file to be read. The readfile function will directly output the content of the file to the output buffer, which is then sent to the browser. This means that the readfile function can output the file content directly without the need to explicitly read the file and output it.

For example, to output an image file (such as logo.png) to the browser, you can use the readfile function like this:

readfile('logo.png');

This will directly output the content of the logo.png file to the browser, without the need for any additional reading and output operations.