The debug_fopen() WordPress PHP function opens a file handle for debugging purposes.
Usage
Here’s an example of using debug_fopen(). We are opening a file named ‘debug.log’ in write mode ‘w’, which means the file content will be truncated to zero length, and we will start writing at the beginning of the file.
$handle = debug_fopen('debug.log', 'w');
Parameters
$filename(string) – Required. The name of the file to be opened.$mode(string) – Required. The type of access required to the stream. For example, ‘w’ for write mode, ‘r’ for read mode, ‘a’ for append mode.
More information
See WordPress Developer Resources: debug_fopen()
This function is used internally by WordPress for debugging purposes.
Examples
Open a file in write mode
This example opens a file named ‘debug.log’ in write mode.
$handle = debug_fopen('debug.log', 'w'); // Opens 'debug.log' in write mode
Open a file in read mode
This example opens a file named ‘read.log’ in read mode.
$handle = debug_fopen('read.log', 'r'); // Opens 'read.log' in read mode
Open a file in append mode
This example opens a file named ‘append.log’ in append mode.
$handle = debug_fopen('append.log', 'a'); // Opens 'append.log' in append mode
Open a file in write and read mode
This example opens a file named ‘write_read.log’ in write and read mode.
$handle = debug_fopen('write_read.log', 'w+'); // Opens 'write_read.log' in write and read mode
Open a file in append and read mode
This example opens a file named ‘append_read.log’ in append and read mode.
$handle = debug_fopen('append_read.log', 'a+'); // Opens 'append_read.log' in append and read mode