Conventional entry points and PARAMIXB

Overview

In the official sample, ExistBlock checks the customization and ExecBlock passes an array as argument four; the entry point reads its elements through PARAMIXB. This does not impose an array on every entry point: shape depends on the actual call. Check type, size and meaning before indexing; PARAMIXB[1] is not always another array. Return exactly what the caller consumes rather than universal .T. or NIL. The demonstration inspects a synthetic array without registering a hook or calling ExecBlock. (Sources: refs. 1–2.)

Syntax

ExecBlock(cPE,...,uParams) -> xReturn; PARAMIXB

Commented example

#Include "Protheus.ch"

User Function Ed572()
    Local uInput := {"ED01",3}
    // Envelope simulation; do not overwrite PARAMIXB in a real entry point.
    If ValType(uInput) == "A"
        If Len(uInput) >= 2
            ConOut(ValType(uInput[1])+" "+ValType(uInput[2]))
        EndIf
    EndIf
Return Nil

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