PRACTICAL GUIDEUnder review

Error handling with BEGIN SEQUENCE and RECOVER

Controls execution interruption and recovery.

Error handling with BEGIN SEQUENCE and RECOVERAdvPL

01 · OVERVIEW

Overview

BEGIN SEQUENCE delimits instructions; Break transfers to RECOVER and USING receives the supplied expression. This example explicitly breaks with a fictional marker. Redirecting runtime errors requires compatible handling such as ErrorBlock invoking Break; the sequence does not automatically capture every fatal failure. Save/restore an overridden ErrorBlock and avoid RETURN paths skipping cleanup. Flow recovery does not automatically roll back transactions, release locks or close resources; the owner must handle them. (Sources: refs. 1–1.)

03 · PRACTICAL EXAMPLE

Commented example

#Include "Protheus.ch"

User Function Ed696()
    Local xError
    Begin Sequence
        // Fictional marker demonstrates transfer without a data error.
        Break("ED696")
    Recover Using xError
        ConOut("Recovery: "+cValToChar(xError))
    End Sequence
Return Nil

Expected result

Displays Recovery: ED696 in the proposed flow. Demonstrates neither fatal-error capture nor rollback. Under review: editorial example neither compiled nor run in Protheus. Check includes, release, RDD and context before testing.

BEST PRACTICES

Do not suppress failures by reporting success. Preserve diagnostics without secrets and test error-path cleanup.
Under review: editorial example neither compiled nor run in Protheus. Check includes, release, RDD and context before testing.

Error handling with BEGIN SEQUENCE and RECOVER

Overview

Commented example

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