The following table lists the ABL elements that are either valid only for accessing a PAS for OpenEdge connection or have special application in PAS for OpenEdge client programming. The remaining sections in this chapter explain how to use these elements.

Table 1. ABL for programming PAS for OpenEdge client procedures
ABL element Description
ASYNC-REQUEST-COUNT One of the following:

1) An INTEGER attribute on the server object handle that returns the number of active asynchronous requests submitted to this server.

2) An INTEGER attribute on the procedure handle that returns the number of currently outstanding asynchronous requests for this procedure. Can be non-zero only if the PROXY and PERSISTENT attributes are both set to TRUE.
Asynchronous request object handle A type of handle that maintains the status of an asynchronous request in an ABL client application. This handle provides methods and attributes that allow you to check the status of a remote procedure (internal or external) that is called asynchronously.
CANCELLED A LOGICAL attribute on the asynchronous request object handle that indicates if the asynchronous request was canceled using either the CANCEL-REQUESTS( ) method or the DISCONNECT( ) method on the associated server handle.
CANCEL-REQUESTS( ) A method on the server object handle that for a session-managed application raises a STOP condition in the context of the currently running asynchronous request and purges the send queue of any asynchronous requests that have not been executed.

For a session-free application, it causes a STOP condition to be raised for all currently running asynchronous requests, and purges the send queue of any asynchronous requests that have not been executed.
CLIENT-CONNECTION-ID A CHARACTER attribute on the server object handle that for a session-managed application returns the connection ID for the PAS for OpenEdge connection associated with this server handle.
COMPLETE A LOGICAL attribute on the asynchronous request object handle that indicates if the asynchronous request is completed and its result is processed on the client. 
CONNECT(
[connection-parameters]
[ , userid]
[ , password]
[ , appserver-info] )
 A method on the server object handle that connects and associates a PAS for OpenEdge instance with the server handle.
CONNECTED( ) A method on the server object handle that returns TRUE if a PAS for OpenEdge instance is currently connected and associated with the server handle.
Note: The CONNECTED( ) method relies on information from the operating system, which may not always be reliable. The method may return TRUE when a connection has been lost.
CREATE SERVER server-handle A statement that creates a server object handle and stores it in a HANDLE variable.
DEFINE INPUT PARAMETER parameter A statement for defining INPUT parameters for an event procedure or method. Each INPUT parameter must correspond to an OUTPUT or INPUT-OUTPUT parameter of the associated asynchronous remote procedure.
DELETE OBJECT handle A statement that you can use to delete certain objects, including server objects, and persistent procedures (local and remote), and asynchronous request objects.
DELETE PROCEDURE procedure-handle A statement that you can use to delete both local and remote procedure objects (persistent procedures).
DISCONNECT( ) A method on the server object handle that disconnects from and removes all reference to the PAS for OpenEdge instance currently associated with the server handle. Any running or pending asynchronous requests submitted by this client are also canceled.
ERROR A LOGICAL attribute on the asynchronous request object handle that indicates that an ERROR condition was returned from the PAS for OpenEdge instance as a result of processing the request.
EVENT-HANDLER A CHARACTER attribute on the asynchronous request object handle that contains the name of the internal procedure or method to be run as the event procedure for this asynchronous request.
EVENT-HANDLER-OBJECT A Progress.Lang.object attribute on the asynchronous request object handle that contains the procedure handle of the event procedure context or the object name containing the event method defined as the asynchronous request callback handler.
EVENT-PROCEDURE A CHARACTER attribute on the asynchronous request object handle that contains the name of the internal procedure to be run as the event procedure for this asynchronous request.
EVENT-PROCEDURE-CONTEXT A HANDLE attribute on the asynchronous request object handle that contains the procedure handle of the active procedure context where the event procedure for this asynchronous request is defined.
FIRST-ASYNC-REQUEST( ) A method on the server object handle that returns the first entry in the list of all current asynchronous request handles for the specified PAS for OpenEdge instance.
FIRST-PROCEDURE A HANDLE attribute on the server object handle that returns the first entry in the list of remote persistent procedures running on the connected PAS for OpenEdge instance.
FIRST-SERVER A HANDLE attribute on the SESSION system handle that returns the handle to the first entry in the chain of server handles for the session.
FUNCTION ... IN procedure-handle A statement that defines a forward reference to a remote user-defined function prototype. When procedure-handle is a proxy procedure handle, the function is defined on the connected PAS for OpenEdge instance in the specified procedure object.
LAST-ASYNC-REQUEST( ) A method on the server object handle that returns the last entry in the list of all current asynchronous request handles for the specified PAS for OpenEdge instance.
LAST-PROCEDURE A HANDLE attribute on the server object handle that returns the last entry in the list of remote persistent procedures running on the connected PAS for OpenEdge instance.
LAST-SERVER A HANDLE attribute on the SESSION system handle that returns the handle to the last entry in the chain of server handles for the client session.
LOCAL-VERSION-INFO An object reference attribute on the SESSION system handle that references a Progress.Lang.OEVersionInfo object, which identifies the current instance of the OpenEdge client AVM, including its OpenEdge version.
NAME A CHARACTER attribute on the server object handle that uniquely identifies the PAS for OpenEdge instance. It returns the connection ID for the PAS for OpenEdge instance associated with the server handle.
NEXT-SIBLING One of the following:

1) A HANDLE attribute on the server object handle that returns the next entry in the list of server handles created for the current ABL session.

2) A HANDLE attribute on the proxy procedure handle that returns the next entry in the list of proxy procedure handles.

3) A HANDLE attribute on the asynchronous request object handle that returns the next entry in the list of asynchronous request handles for asynchronous remote procedures submitted for execution on the same PAS for OpenEdge instance.
PERSISTENT A LOGICAL attribute on procedure handles and the THIS-PROCEDURE system handle that is TRUE if the specified procedure is running persistently as a procedure object.
PERSISTENT-PROCEDURE A HANDLE attribute on the asynchronous request object handle that returns the proxy procedure handle to the remote persistent procedure that contains the internal procedure executed for the specified asynchronous request. If the request is for an external, rather than an internal, procedure, this attribute returns an invalid handle.
PREV-SIBLING One of the following:
  1. A HANDLE attribute on the server object handle that returns the previous entry in the list of server handles created for the current ABL session.
  2. A HANDLE attribute on the proxy procedure handle that returns the previous entry in the list of proxy procedure handles.
  3. A HANDLE attribute on the asynchronous request object handle that returns the previous entry in the list of asynchronous request handles for asynchronous remote procedures submitted for execution on the same PAS for OpenEdge instance.
PROCEDURE-COMPLETE The event returned for an asynchronous request object handle that indicates the associated remote procedure has completed execution and, as a result, causes execution of the specified event procedure as specified by the EVENT-PROCEDURE and EVENT-PROCEDURE-CONTEXT attributes.
PROCEDURE-NAME A CHARACTER attribute on the asynchronous request object handle that provides the name of the remote procedure executed to instantiate this asynchronous request handle.
PROCESS EVENTS A statement that you can use to handle any pending PROCEDURE-COMPLETE events for asynchronous requests. You can also use any blocking I/O statement, such as the WAIT-FOR statement.
PROXY A LOGICAL attribute on a procedure handle that is TRUE if the procedure handle is a proxy handle for a persistent, single-run, or singleton procedure running remotely in the context of a PAS for OpenEdge instance.
Proxy procedure handle A type of procedure object handle that references the context of a remote persistent, single-run, or singleton procedure, providing access to its remote internal procedures and user-defined functions.
QUIT A LOGICAL attribute on the asynchronous request object handle that indicates a QUIT condition was returned from the PAS for OpenEdge instance as a result of processing the request.
REQUEST-INFO An object reference attribute on a server object handle (or on the returned asynchronous request object handle for an asynchronous remote request), which references a Progress.Lang.OERequestInfo instance. This class instance provides information about the next remote procedure request to be run on the PAS for OpenEdge instance connected using the associated server object handle.
RESPONSE-INFO An object reference attribute on a server object handle (or on the returned asynchronous request object handle for an asynchronous remote request), which references a Progress.Lang.OERequestInfo instance. This class instance provides information about the remote procedure response most recently received from the PAS for OE instance connected using the associated server object handle. 
RUN ... [PERSISTENT 
| SINGLE-RUN | SINGLETON...]
  ON [SERVER]server-handle  
 [TRANSACTION DISTINCT]  
 [ASYNCHRONOUS ...] ...
 The statement that executes an external (remote) procedure on a connected PAS for OpenEdge instance specified by server-handle, in a transaction that is distinct from the client. With the PERSISTENT option, it instantiates the procedure as a persistent procedure object. With the SINGLE-RUN or SINGLETON option, intended for use on a session-free or unbound session-managed connection, the procedure is instantiated on the server without causing the client to be bound to the server session. With the ASYNCHRONOUS option (not valid with SINGLE-RUN or SINGLETON), the procedure executes asynchronously with respect to the client. This option also optionally specifies the associated asynchronous request object handle and event procedure to handle results of the request. If server-handle is the SESSION system handle, the external procedure executes synchronously in the local session.
RUN ... IN procedure-handle   [ASYNCHRONOUS ...] ... The statement that executes an internal (remote) procedure on a connected server, where procedure-handle specifies a remote persistent, single-run, or singleton procedure that defines the internal procedure on the PAS for OpenEdge instance. With the ASYNCHRONOUS option, the internal procedure executes asynchronously with respect to the client. This option also optionally specifies the associated asynchronous request handle and event procedure or method to handle results of the request. If procedure-handle is the handle to a local persistent procedure, the internal procedure executes synchronously in the local session.
SELF A system handle that, in the context of an event procedure, returns the asynchronous request object handle of the completed request for which the event procedure is executing.
SERVER One of the following:
  1. A HANDLE attribute on a remote persistent procedure handle that returns the server object handle to the PAS for OpenEdge instance on which the specified remote persistent procedure runs. Valid only if the PROXY and PERSISTENT attributes are both TRUE.
  2. A HANDLE attribute on the asynchronous request object handle that returns the server handle of the PAS for OE instance where this asynchronous request was submitted for execution. If the request is run in the local session (using the SESSION system handle), the attribute is set to the SESSION handle.
Server object handle A type of handle that provides a connection to a PAS for OE instance in an ABL client application. This handle provides server object methods and attributes that allow you to connect and manage the PAS for OpenEdge instance.
SINGLE-RUN A LOGICAL attribute on procedure handles and the THIS-PROCEDURE system handle (in a server session) that is TRUE if the specified procedure is running as a single-run object.
SINGLETON A LOGICAL attribute on procedure handles and the THIS-PROCEDURE system handle (in a server session) that is TRUE if the specified procedure is running as a singleton object.
STOP A LOGICAL attribute on the asynchronous request object handle that indicates a STOP condition was returned from the PAS for OpenEdge instance as a result of processing the request.
TYPE One of the following:1) A CHARACTER attribute on the server object handle that returns the handle type, which is "SERVER" for a server object handle. 2) A CHARACTER attribute on the asynchronous request object handle that provides the handle type, which is "ASYNC-REQUEST" for an asynchronous request object handle.
WAIT-FOR ... A statement that you can use to handle any pending PROCEDURE-COMPLETE events for asynchronous requests. You can also use PROCESS EVENTS or any other blocking I/O statement, such as the PROMPT-FOR statement.