PRACTICAL GUIDEUnder review

RecLock and MsUnlock in introductory maintenance

Checks a lock before changing a record.

RecLock and MsUnlock in introductory maintenanceAdvPL

01 · OVERVIEW

Overview

RecLock with .F. tries to lock the current record; .T. starts an insert. Assign fields only after .T., then finish with MsUnlock in the same alias. SQL cursors and read-only aliases cannot use this flow. Within an explicit transaction MsUnlock is still required, but locking can persist until transaction end. This example is only a no-assignment update cycle on an open positioned sandbox ZZ1, not a complete registration routine. Prefer supported automatic routines/models for standard tables. (Sources: refs. 1–3.)

03 · PRACTICAL EXAMPLE

Commented example

#Include "Protheus.ch"

User Function Ed613()
    // Run only on an open, positioned sandbox ZZ1.
    If Select("ZZ1") > 0
        If !ZZ1->(Eof())
            If RecLock("ZZ1",.F.)
                // Validated assignments would be made here.
                ZZ1->(MsUnlock())
            EndIf
        EndIf
    EndIf
Return Nil

Expected result

When preconditions hold, attempts to lock and finish without field changes. No writes on lock failure. Under review: editorial example neither compiled nor run in Protheus. Check includes, release, RDD and context before testing.

BEST PRACTICES

SoftLock is not proof that RecLock succeeded. Plan errors/restoration without unlocking another owner’s resources.
Under review: editorial example neither compiled nor run in Protheus. Check includes, release, RDD and context before testing.

RecLock and MsUnlock in introductory maintenance

Overview

Commented example

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