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LogCancel

procedure LogCancel(const aMesg: string);

Example​

procedure ScriptEvent(var Value: variant);
begin
  if Value = '' then
  begin
    LogCancel('No source value was available; the flow is being cancelled.');
    Exit; // LogCancel does not itself exit the current script procedure.
  end;
end;

Usage​

LogCancel adds a cancelled item to the current flow log and marks the flow cancelled unless a more severe status already exists.

Parameters

NameTypeDescription
aMesgstring, constHuman-readable cancellation reason stored as a level-5 log item. Empty text is accepted.

Additional Technical Info​

LogCancel adds a Cancelled item to the current flow log and normally changes the overall log status to flsCancelled. The action engine stops dispatching further action steps after the current script returns because its execution loop checks the cancelled state.

The call does not raise an exception, exit the current script procedure or undo work already performed. Use an explicit Exit when statements later in the same procedure must not run. The example is fictional and source-reviewed; it was not executed.

Implementation trace

  1. TvxScripter.LogCancel calls Log.Cancelled(aMesg).
  2. TvxLog.Cancelled calls MessageLog with native level 5 (flsCancelled).
  3. MessageLog asks the log to adopt Cancelled status, creates a TvxLogItem, stores the description and level, and updates the log end time.

The resulting item caption is Cancelled. It is not flagged as a User item internally, unlike Issue, Duplicate and the user-specific Info/Warning/Error levels.

Overall-status behavior

Flow status is monotonic by the native enumeration's numeric order. Cancelled (5) replaces Successful, Warning, Issue or Duplicate, but cannot replace an existing Error (6). If Error already exists, the cancellation item is still added, but Log.IsCancelled remains false because the overall state stays Error; processing is already destined to stop through Log.Status=False.

Cancelled status leaves the log's Boolean Status true. Stopping occurs through the separate IsCancelled check, not through a false Boolean result. This distinction affects code that reads only Log.Status.

Persistence and flow effects

The default flow configuration saves Successful, Warning, Issue, Duplicate and Error logs, but excludes Cancelled. If cancellation remains the final status, the item and other current log content may be visible during execution yet not be persisted to VxData. Administrators can change the configured save-status set.

Cancellation also prevents deferred InvoiceIssue data from being saved because issue finalization requires not Log.IsCancelled. It does not roll back arbitrary external effects already committed by script code; transaction/file behavior remains the responsibility of the affected API and later flow finalization.

Text, errors and limits

Velox performs no trim, formatting, redaction or length check here. When the normalized VX_LOG_ITEM row is written, the description is copied to a database-limited prefix (448 characters with the SQL-2014-support branch, otherwise 840); the serialized log representation may retain more. Avoid secrets and excessive payloads.

Allocation or log-object failures can propagate, but there is no expected database access during this immediate call. Database persistence happens later if the final status is configured to save.

Related entries

Created 2026-07-15