Command-line reference

Options:

Option	Meaning
--provider ca or --provider pva	Default for unprefixed names
-w seconds, --timeout seconds	Connection/read deadline; default 5, maximum 3600
--read-only	Disable writes throughout the process
--max-elements count	Retain at most this many array values; default 16384
--history count	Retain at most this many monitor events per PV; default 10000
--history-memory MB	Memory limit for the retained events of all PVs together; default 256, range 16–65536
--info or -info	Print one metadata snapshot per PV and exit without a display
--json	JSON output with --info; values remain exact strings
--session file.qtp	Open a saved PV workspace
-h, --help, --version	Command-line help/version without a display

-- ends QtProbe's options: later arguments are PV names, even ones starting with - (Qt still reads its own options, such as -style, anywhere). Count limits must be between 1 and 1000000. Invalid arguments exit with status 2. --info returns 1 if any PV is unavailable or its data/metadata times out, and 0 on success. GUI discovery continues after the deadline and recovers when an IOC returns. PVA requires an EPICS Base built with pvAccess and pvData. The --info report alone goes to standard output; EPICS library diagnostics go to standard error. When scripts capture --info output, run a caRepeater service or make sure the caRepeater on PATH is from EPICS 7.0.4 or later: an older repeater started on demand keeps the caller's output open.