Rules / Types, classes & roles / domain-specific

IO::Special Reference

Path to special I/O device

What it is #

Routines #

Signatures are reproduced from the documentation, including their declared return types. A routine listed here is part of the type's published interface; whether Raku++ implements it is a separate question, answered by the examples below.

method new #

method new(:$!what!)

Takes a single required attribute what. It is unlikely that you will ever need to construct one of these objects yourself.

method what #

Returns one of the strings '<STDIN>', '<STDOUT>', or '<STDERR>', specifying the type of the special IO device.

method WHICH #

method WHICH(IO::Special:D: --> Str)

Returns Str.

This returns a string that identifies the object. The string is composed by the type of the instance (IO::Special) and the what attribute:

method Str #

method Str(IO::Special:D:)

This returns '<STDIN>', '<STDOUT>', or '<STDERR>' as appropriate.

method IO #

method IO(IO::Special:D: --> IO::Special)

Returns IO::Special.

Returns the invocant.

method e #

method e(IO::Special:D: --> True)

Returns True.

The 'exists' file test operator, always returns True.

method d #

method d(IO::Special:D: --> False)

Returns False.

The 'directory' file test operator, always returns False.

method f #

method f(IO::Special:D: --> False)

Returns False.

The 'file' file test operator, always returns False.

method s #

method s(IO::Special:D: --> 0)

Returns 0.

The 'size' file test operator, always returns 0.

method l #

method l(IO::Special:D: --> False)

Returns False.

The 'symbolic links' file test operator, always returns False.

method r #

method r(IO::Special:D: --> Bool)

Returns Bool.

The 'read access' file test operator, returns True if and only if this instance represents the standard input handle(<STDIN>).

method w #

method w(IO::Special:D: --> Bool)

Returns Bool.

The 'write access' file test operator, returns True only if this instance represents either the standard output (<STOUT>) or the standard error (<STDERR>) handle.

method x #

method x(IO::Special:D: --> False)

Returns False.

The 'execute access' file test operator, always returns False.

method modified #

method modified(IO::Special:D: --> Instant)

Returns Instant.

The last modified time for the filehandle. It always returns an Instant type object.

method accessed #

method accessed(IO::Special:D: --> Instant)

Returns Instant.

The last accessed time for the filehandle. It always returns an Instant type object.

method changed #

method changed(IO::Special:D: --> Instant)

Returns Instant.

The last changed time for the filehandle. It always returns an Instant type object.

method mode #

method mode(IO::Special:D: --> Nil)

Returns Nil.

The mode for the filehandle, it always returns Nil

Examples, run three ways #

Every example below comes from the official documentation, together with the output that documentation asserts. Each was then executed by Rakudo and by Raku++ when this page was built. Where the three agree, one result is shown; where they do not, all three are — because which of them is wrong is exactly the information worth having.

1 doc-drift · 1 no-output · 2 ok

class IO::Special does IO { }

Not executed: the documentation states no expected output for this example.

say $*IN.path.what;  # OUTPUT: «<STDIN>␤»
say $*OUT.path.what; # OUTPUT: «<STDOUT>␤»
say $*ERR.path.what; # OUTPUT: «<STDERR>␤»
Output
<STDIN>
<STDOUT>
<STDERR>

Documentation, Rakudo and Raku++ all agree.

$*IN.path.what;  # OUTPUT: «<STDIN>␤»
$*IN.path.WHICH; # OUTPUT: «IO::Special<STDIN>␤»
Documentation
<STDIN>
IO::Special<STDIN>
Rakudo
Raku++

Both engines agree; the documentation states something else. Trust the engines.

say $*IN.path.IO.what;  # OUTPUT: «<STDIN>␤»
say $*IN.path.what;     # OUTPUT: «<STDIN>␤»
Output
<STDIN>
<STDIN>

Documentation, Rakudo and Raku++ all agree.