mkfifo: some workaround to ensure reasonably unique id, even on Cygwin where $PPID might fall back on odd default;
#!/usr/bin/env bash
#
# Author: Makarius
#
# DESCRIPTION: create named pipe
PRG="$(basename "$0")"
function usage()
{
echo
echo "Usage: isabelle $PRG [SUFFIX]"
echo
echo " Create a temporary named pipe and return its name."
echo
exit 1
}
function fail()
{
echo "$1" >&2
exit 2
}
## main
SUFFIX=""
[ "$#" != 0 ] && { SUFFIX="-$1"; shift; }
[ "$#" != 0 ] && usage
ID="$PPID"
[ "$ID" = 0 -o "$ID" = 1 ] && ID="$$" # Cygwin workaround
FIFO="/tmp/isabelle-fifo${ID}${SUFFIX}"
mkfifo -m 600 "$FIFO" || fail "Failed to create fifo: $FIFO"
echo "$FIFO"