Similar to the /inet special files, if gawk
is configured with the --enable-portals option
(see Quick Installation),
then gawk treats
files whose pathnames begin with /p as 4.4 BSD-style portals.
When used with the `|&' operator, gawk opens the file for two-way communications. The operating system's portal mechanism then manages creating the process associated with the portal and the corresponding communications with the portal's process.