IPC::Run::IO(3)       User Contributed Perl Documentation      IPC::Run::IO(3)


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 v5.38.2                      2024-07-13                   IPC::Run::IO(3)