Description:
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When using the PHP CLI executable, the script can be named on the command line, or fed to PHP through standard input. If using standard input, the file constants STDIN, STDOUT, and STDERR are undefined.  I can understand not defining STDIN, since the script is read from there, but why are STDOUT and STDERR not defined?


Reproduce code:
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<?php
fwrite(STDOUT, "Hello, standard output\n");
fwrite(STDERR, "Hello, standard error\n");


Expected result:
----------------
Written to stdout:  Hello, standard output
Written to stderr:  Hello, standard error


Actual result:
--------------
When run as: $ php nostd.php
   Works as expected.

When run as: $ php < nostd.php
   This output:
PHP Notice:  Use of undefined constant STDOUT - assumed 'STDOUT' in ...
PHP Warning:  fwrite(): supplied argument is not a valid stream resource in...
PHP Notice:  Use of undefined constant STDERR - assumed 'STDERR' in ...
PHP Warning:  fwrite(): supplied argument is not a valid stream resource in ...