Bar States

barstate.* is a namespace of booleans that describe where the script currently is in the per-bar loop.

Core booleans

Name	True when
`barstate.isfirst`	The script is on the first bar of the chart's history.
`barstate.islast`	The script is on the current (newest) bar in the chart's data set.
`barstate.ishistory`	The current bar is a confirmed historical bar.
`barstate.isrealtime`	The current bar is being formed in real time.
`barstate.isconfirmed`	The current bar has closed (true on every historical bar; on the live bar only on its very last tick before close).
`barstate.isnew`	The runtime has just advanced to a new bar — true on the first tick of each new bar.
`barstate.islastconfirmedhistory`	The last historical bar BEFORE the realtime pass begins. Useful for one-shot setup that must survive to realtime.

Historical pass vs realtime pass

Historical bars run once each. On every one barstate.ishistory = true, barstate.isconfirmed = true.
The live bar re-runs on every tick. On most ticks barstate.isrealtime = true, barstate.isconfirmed = false. On its final tick (bar close) barstate.isconfirmed = true and the bar joins the historical pass.

Common patterns

One-time setup at the first bar

if barstate.isfirst
    log.info("Script loaded on " + syminfo.ticker)

Finalise only on confirmed bars

if barstate.isconfirmed and ta.crossover(close, ta.sma(close, 20))
    strategy.entry("Long", strategy.long)

Confirmed-only signals avoid intra-bar flapping — the entry fires once at bar close rather than every tick.

Draw once per bar, update on live

var label l = na
if barstate.isnew
    label.delete(l)
    l := label.new(bar_index, high, "")
if not barstate.isconfirmed
    label.set_text(l, str.tostring(close, "#.##"))

Snapshot the last historical bar

var float lastHistoricalClose = na
if barstate.islastconfirmedhistory
    lastHistoricalClose := close

Values written in islastconfirmedhistory survive into the realtime pass — the snapshot/restore cycle preserves var state.

See also