Isigetnextnvindex(), Isigetnvindex() – Echelon ISI User Manual

Page 148

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ISI Programmer’s Guide

146

IsiGetNextNvIndex()

unsigned IsiGetNextNvIndex(unsigned

Assembly

, unsigned

Offset

, unsigned

Previous

);

Returns the network variable index of the network variable at the specified offset

within the specified assembly, following the network variable specified by the

Previous

index. Returns ISI_NO_INDEX if there are no more network variables,

or a valid network variable index 1– 254 otherwise. The

Offset

parameter is

zero-based and relates to the selector number

Offset

within the assembly that is

used with the enrollment of this assembly.

This function is a forwarder to isiGetNextNvIndex().

The isiGetNextNvIndex() forwardee always returns ISI_NO_INDEX.

Applications may override IsiGetNextNvIndex() to map multiple local network

variables to a single network variable selector. The ISI application is responsible
for observing the various binding and protocol limitations when using this

feature.

The isiGetNextNvIndex() forwardee assumes the default assembly numbering

scheme that is described in

Assembly Number Allocation

earlier.

Applications overriding IsiGetNextNvIndex() should also override
IsiGetNvIndex().

This function operates whether the ISI engine is running or not.

IsiGetNvIndex()

unsigned IsiGetNvIndex(unsigned

Assembly

, unsigned

Offset

);

Returns the network variable index 0 – 254 of the network variable at the

specified offset within the specified assembly, or ISI_NO_INDEX if no such
network variable exists. This function must return at least one valid network

variable index for each assembly number returned by IsiGetAssembly() and
IsiGetNextAssembly(). The

Offset

parameter is zero-based and relates to the

selector number

Offset

that is used with the enrollment of this assembly.

This function is a forwarder to isiGetNvIndex().

The isiGetNvIndex() forwardee returns

Assembly

+

Offset

.

The isiGetNvIndex() forwardee assumes the default assembly numbering scheme

that is described in

Assembly Number Allocation

earlier.

Applications overriding IsiGetNvIndex() should also override
IsiGetNextNvIndex().

This function operates whether the ISI engine is running or not.

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