PerlIO::scalar - memory IO, scalar IO
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;
Perl Programmers Reference Guide                             PerlIO::scalar(3)
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.
IMPLEMENTATION NOTE
       "PerlIO::scalar" only exists to use XSLoader to load C code that
       provides support for treating a scalar as an "in memory" file.  One
       does not need to explicitly "use PerlIO::scalar".
ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:
       +---------------+-----------------------+
       |ATTRIBUTE TYPE |   ATTRIBUTE VALUE     |
       +---------------+-----------------------+
       |Availability   | runtime/perl-532      |
       +---------------+-----------------------+
       |Stability      | Pass-through volatile |
       +---------------+-----------------------+
NOTES
       Source code for open source software components in Oracle Solaris can
       be found at https://www.oracle.com/downloads/opensource/solaris-source-
       code-downloads.html.
       This software was built from source available at
       https://github.com/oracle/solaris-userland.  The original community
       source was downloaded from
       http://www.cpan.org/src/5.0/perl-5.32.0.tar.gz.
       Further information about this software can be found on the open source
       community website at https://www.perl.org/.
perl v5.32.0                      2020-06-14                 PerlIO::scalar(3)