IPC::Run::IO(3pm) User Contributed Perl Documentation IPC::Run::IO(3pm)
NAME
IPC::Run::IO -- I/O channels for IPC::Run.
SYNOPSIS
NOT IMPLEMENTED YET ON Win32! Win32 does not allow select() on normal
file descriptors; IPC::RUN::IO needs to use IPC::Run::Win32Helper to do
this.
use IPC::Run qw( io );
## The sense of '>' and '<' is opposite of perl's open(),
## but agrees with IPC::Run.
$io = io( "filename", '>', \$recv );
$io = io( "filename", 'r', \$recv );
## Append to $recv:
$io = io( "filename", '>>', \$recv );
$io = io( "filename", 'ra', \$recv );
$io = io( "filename", '<', \$send );
$io = io( "filename", 'w', \$send );
$io = io( "filename", '<<', \$send );
$io = io( "filename", 'wa', \$send );
## Handles / IO objects that the caller opens:
$io = io( \*HANDLE, '<', \$send );
$f = IO::Handle->new( ... ); # Any subclass of IO::Handle
$io = io( $f, '<', \$send );
require IPC::Run::IO;
$io = IPC::Run::IO->new( ... );
## Then run(), harness(), or start():
run $io, ...;
## You can, of course, use io() or IPC::Run::IO->new() as an
## argument to run(), harness, or start():
run io( ... );
DESCRIPTION
This class and module allows filehandles and filenames to be harnessed
for I/O when used IPC::Run, independent of anything else IPC::Run is
doing (except that errors & exceptions can affect all things that
IPC::Run is doing).
SUBCLASSING
INCOMPATIBLE CHANGE: due to the awkwardness introduced in ripping
pseudohashes out of Perl, this class no longer uses the fields pragma.
SUBROUTINES
new I think it takes >> or << along with some other data.
TODO: Needs more thorough documentation. Patches welcome.
filename
Gets/sets the filename. Returns the value after the name change,
if any.
init
Does initialization required before this can be run. This includes
open()ing the file, if necessary, and clearing the destination
scalar if necessary.
open
If a filename was passed in, opens it. Determines if the handle is
open via fileno(). Throws an exception on error.
open_pipe
If this is a redirection IO object, this opens the pipe in a
platform independent manner.
close
Closes the handle. Throws an exception on failure.
fileno
Returns the fileno of the handle. Throws an exception on failure.
mode
Returns the operator in terms of 'r', 'w', and 'a'. There is a
state 'ra', unlike Perl's open(), which indicates that data read
from the handle or file will be appended to the output if the
output is a scalar. This is only meaningful if the output is a
scalar, it has no effect if the output is a subroutine.
The redirection operators can be a little confusing, so here's a
reference table:
> r Read from handle in to process
< w Write from process out to handle
>> ra Read from handle in to process, appending it to existing
data if the destination is a scalar.
<< wa Write from process out to handle, appending to existing
data if IPC::Run::IO opened a named file.
op Returns the operation: '<', '>', '<<', '>>'. See "mode" if you
want to spell these 'r', 'w', etc.
binmode
Sets/gets whether this pipe is in binmode or not. No effect off of
Win32 OSs, of course, and on Win32, no effect after the harness is
start()ed.
dir Returns the first character of $self->op. This is either "<" or
">".
poll
TODO: Needs confirmation that this is correct. Was previously
undocumented.
I believe this is polling the IO for new input and then returns
undef if there will never be any more input, 0 if there is none
now, but there might be in the future, and TRUE if more input was
gotten.
AUTHOR
Barrie Slaymaker <barries@slaysys.com>
TODO
Implement bidirectionality.
perl v5.34.0 2022-08-11 IPC::Run::IO(3pm)
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