Interfaces

The IPB_VM interface is used to load PowerBuilder
applications in third-party applications and interoperate with the
PowerBuilder virtual machine (PBVM).

IPB_Session is an abstract interface that defines
methods for performing various actions such as accessing PowerScript
data, creating PowerBuilder objects, and calling PowerScript functions.

The IPB_Value and IPB_Arguments interfaces
enable you to pass values between the PowerBuilder VM and PowerBuilder
extension modules.

The IPB_Value interface represents a PowerBuilder
value, which could be one of the PowerBuilder standard datatypes
such as integer, long, string, and so forth. It provides information
about each variable, including its type, null flag, access privileges,
array or simple type, and reference type.

The IPB_Arguments interface represents the arguments
passed to a PowerScript function and is used to access the data.

The IPB_ResultSetAccessor and IPB_RSItemData
interfaces enable you to access data in a DataWindow or DataStore.

All PowerBuilder native classes inherit from the IPBX_NonVisualObject interface
or the IPBX_VisualObject interface, which in turn inherit
from the IPBX_UserObject interface. You must implement
the Invoke method in the inherited class to enable
PowerBuilder to invoke methods in the native class.

Marshaler extensions contain a class that inherits from the
IPBX_Marshaler interface. You must implement the InvokeRemoteMethod method
in the inherited class to enable PowerBuilder to invoke methods
on remote objects represented by a proxy.

Structures

The PBCallInfo structure holds arguments and return type information
for function calls between PBNI and PowerBuilder. To access the
information in PBCallInfo, use the IPB_Arguments interface.

The PBArrayInfo structure stores information about arrays.

The PB_DateData, PB_TimeData, and PB_DateTimeData
structures are used to pass DataWindow and DataStore data.

Global functions

Every PowerBuilder
extension object must export global functions that enable the PowerBuilder
VM to create instances of the object and use its methods. The PBX_GetDescription function
describes the classes and functions in the extension. The PBX_CreateNonVisualObject function
enables the PBVM to create instances of the nonvisual classes in
an extension, and the PBX_CreateVisualObject function
does the same for visual classes.

Helper classes

Several helper classes,
such as PBObjectCreator, PBArrayAccessor, and PBEventTrigger, make
it easier to program with PBNI.

Interaction between an extension and the PBVM

The
following diagram summarizes how an extension interacts with the PBVM.

Figure 1-2: Interaction between an extension and the PowerBuilder
VM