The CLI SAPI defines a few constants for I/O streams to make programming for the command line a bit easier.
Constant | Description |
---|---|
STDIN |
An already opened stream to stdin. This saves opening it with
<?php If you want to read single line from stdin, you can use
<?php
|
STDOUT | An already opened stream to stdout. This saves opening it with
<?php
|
STDERR |
An already opened stream to stderr. This saves opening it with
<?php
|
Given the above, you don't need to open e.g. a stream for stderr yourself but simply use the constant instead of the stream resource:
php -r 'fwrite(STDERR, "stderr\n");'
You do not need to explicitly close these streams, as they are closed automatically by PHP when your script ends.
Note: These constants are not available in case of reading PHP script from stdin.