PerlIO::scalar(3perl)  Perl Programmers Reference Guide  PerlIO::scalar(3perl)


NAME
       PerlIO::scalar - in-memory IO, scalar IO

SYNOPSIS
          my $scalar = '';
          ...
          open my $fh, "<",  \$scalar or die;
          open my $fh, ">",  \$scalar or die;
          open my $fh, ">>", \$scalar or die;

       or

          my $scalar = '';
          ...
          open my $fh, "<:scalar",  \$scalar or die;
          open my $fh, ">:scalar",  \$scalar or die;
          open my $fh, ">>:scalar", \$scalar or die;

DESCRIPTION
       A filehandle is opened but the file operations are performed
       "in-memory" on a scalar variable.  All the normal file operations can
       be performed on the handle. The scalar is considered a stream of bytes.
       Currently fileno($fh) returns -1.

       Attempting to open a read-only scalar for writing will fail, and if
       warnings are enabled, produce a warning.

IMPLEMENTATION NOTE
       "PerlIO::scalar" only exists as a stub. One does not need to explicitly
       "use PerlIO::scalar".

perl v5.42.2                      2026-08-11             PerlIO::scalar(3perl)