Document revision date: 30 March 2001

## OpenVMS System Services Reference Manual

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## $ICC_CONNECTW

> Establishes a link between two ICC associations.

> The $ICC_CONNECTW service completes synchronously; that is, it returns to the caller after the server has either accepted or rejected the connection request.

> For asynchronous completion, use the $ICC_CONNECT service; $ICC_CONNECT returns to the caller as soon as the connection request has been sent to the server, without waiting for a response from the server.

> On Alpha, this service accepts 64-bit addresses.

### Format

> SYS$ICC_CONNECTW ios_icc, [astadr], [astprm], assoc_handle, conn_handle, remote_assoc, [remote_node], [user_context], [conn_buf], [conn_buf_len], [return_buf], [return_buf_len], [retlen_addr], [flags]

### C Prototype:

> int sys$icc_connectw (struct _ios_icc *ios_icc, void (*astadr)(__unknown_params), __int64 astprm, unsigned int assoc_handle, unsigned int *conn_handle, void *remote_assoc, void *remote_node, unsigned int user_context, char *conn_buf, unsigned int conn_buf_len, char *return_buf, unsigned int return_buf_len, unsigned int *retlen_addr, unsigned int flags);

## $ICC_DISCONNECT

> Terminates the specified connection.

> On Alpha systems, this service accepts 64-bit addresses.

### Format

> SYS$ICC_DISCONNECT conn_handle ,iosb ,[astadr] ,[astprm] ,[disc_buf] ,[disc_buf_len]

### C Prototype:

> int sys$icc_disconnect (unsigned int conn_handle, struct _iosb, *iosb, void (*astadr)(__unknown_params), __int64 astprm, char * disc_buf, unsigned int disc_buf_len);

### Arguments

> #### conn_handle

> OpenVMS usage: | connection_id
> type: | longword (unsigned)
> access: | read only
> mechanism: | by value

> The ID of the connection to be disconnected.

> #### iosb

> OpenVMS usage: | io_status_block
> type: | quadword (unsigned)
> access: | write only
> mechanism: | by 32-bit or 64-bit reference (Alpha)
> mechanism: | by 32-bit reference (VAX)

> I/O status block:

Completion status values:

SS$_NORMAL, SS$_EXQUOTA, SS$_LINKDISCON, $ICC_REJECT

#### astadr

OpenVMS usage: | ast_procedure
type: | procedure_entry_mask
access: | call without stack unwinding
mechanism: | by 32-bit or 64-bit linkage reference (Alpha)
mechanism: | by 32-bit reference (VAX)

The AST routine to be executed when the operation completes.

#### astprm

OpenVMS usage: | user_arg
type: | quadword (unsigned) (Alpha), longword (unsigned) (VAX)
access: | read only
mechanism: | by 64-bit value (Alpha)
mechanism: | by 32-bit value (VAX)

The parameter to be passed to the AST routine.

#### disc_buf

OpenVMS usage: | byte_stream
type: | character-coded text string
access: | read only
mechanism: | by 32-bit or 64-bit reference (Alpha)
mechanism: | by 32-bit reference (VAX)

A buffer of up to 1000 bytes of disconnect data to be sent to the partner in the connection when notifying it that disconnection is being initiated. Delivery of this data is not guaranteed.

#### disc_buf_len

OpenVMS usage: | buffer_length
type: | longword (unsigned)
access: | read only
mechanism: | by value

The number of bytes in disc_buf to be sent.

### Description

> This service must be called in the mode in which the association was opened.

> This service terminates the specified connection. After this service is called, no further communication is possible over this connection. All outstanding data transmission and reception functions are terminated with an error before completion is signaled by calling the AST (if supplied).

> A connection may be disconnected by either party. Proper programming procedure for network communications strongly recommends that the party that last received a message initiate the disconnection. If the party that last sent a message initiates the disconnection, there is no guarantee that the message was delivered.

> Similarly, although this interface provides the ability to send disconnect data, only noncritical information should be transmitted with the disconnect data mechanism, because there is no guarantee that the data will have been received or acted upon by the other party to the connection.

> Required Access or Privileges

> None.

> Required Quota

> BYTLM (disc_buf)

> Related Services

> $ICC_ACCEPT, $ICC_CLOSE_ASSOC, $ICC_CONNECT, $ICC_CONNECTW, $ICC_DISCONNECTW, $ICC_OPEN_ASSOC, $ICC_RECEIVE, $ICC_RECEIVEW, $ICC_REJECT, $ICC_REPLY, $ICC_REPLYW, $ICC_TRANSCEIVE, $ICC_TRANSCEIVEW, $ICC_TRANSMIT, $ICC_TRANSMITW

### Condition Values Returned

> SS$_NORMAL | Normal successful completion.
> SS$_ACCVIO | Access violation on parameter.
> SS$_BADPARAM | Bad parameter value specified.
> SS$_INSFMEM | Not enough nonpaged pool.
> SS$_IVBUFLEN | The length of the disconnect data buffer is more than 1000 bytes.
> SS$_IVCHAN | Unknown connection specified or invalid connection handle.
> SS$_IVMODE | Attempted to disconnect a connection from a more privileged access mode than the requested connection.
> SS$_LINKDISCON | The remote association closed the connection before it was accepted or rejected.
> SS$_TOO_MANY_ARGS | Too many arguments specified.

## $ICC_DISCONNECTW

> Terminates a link between two ICC associations.

> The $ICC_DISCONNECTW service completes synchronously; that is, it returns to the caller after the connection has completely finished the disconnection request.

> For asynchronous completion, use the $ICC_DISCONNECT service; $ICC_DISCONNECT returns to the caller as soon as the disconnection request has been sent to the transport layer, without waiting for notification that the disconnection has completed.

> On Alpha, this service accepts 64-bit addresses.

### Format

> SYS$ICC_DISCONNECTW conn_handle ,iosb ,[astadr] ,[astprm] ,[disc_buf] ,[disc_buf_len]

### C Prototype:

> int sys$icc_disconnectw (unsigned int conn_handle, struct _iosb, *iosb, void (*astadr)(__unknown_params), __int64 astprm, char * disc_buf, unsigned int disc_buf_len);

## $ICC_OPEN_ASSOC

> Declares an application association with ICC.

> On Alpha systems, this service accepts 64-bit addresses.

### Format

> SYS$ICC_OPEN_ASSOC assoc_handle ,[assoc_name] ,[logical_name] ,[logical_table] ,[conn_event_rtn] ,[disc_event_rtn] ,[recv_rtn] ,[maxflowbufcnt] ,[prot]

### C Prototype:

> int sys$icc_open_assoc (unsigned int *assoc_handle, void *assoc_name, void *logical_name, void *logical_table, void (*conn_event_rtn)(__unknown_params), void (*disc_event_rtn)(__unknown_params), void (*recv_rtn)(__unknown_params), unsigned int maxflowbufcnt, unsigned int prot);

### Arguments

> #### assoc_handle

> OpenVMS usage: | association_id
> type: | longword (unsigned)
> access: | write only
> mechanism: | by 32-bit or 64-bit reference (Alpha)
> mechanism: | by 32-bit reference (VAX)

> The 32-bit or 64-bit address (on Alpha systems) or the 32-bit address (on VAX systems) of a longword into which $ICC_OPEN_ASSOC writes the handle assigned to the opened association.

> #### assoc_name

> OpenVMS usage: | char_string
> type: | character-coded text string
> access: | read only
> mechanism: | by 32-bit or 64-bit descriptor (Alpha)
> mechanism: | by 32-bit descriptor (VAX)

> An ASCII character string of up to 31 characters in length specifying the name of the application opening the association. Null (0 length), and empty or blank association names are not allowed. If this argument is omitted (that is, a zero is passed in by value), it signifies that the user wants to open the default association. This argument is case sensitive.

> #### logical_name

> OpenVMS usage: | logical name
> type: | character-coded text string
> access: | read only
> mechanism: | by 32-bit or 64-bit descriptor (Alpha)
> mechanism: | by 32-bit descriptor (VAX)

> A logical name in a clusterwide logical name table used to maintain the simple association registry. The logical name represents the name of the service provided by the application. Logical names are case sensitive.

> #### logical_table

> OpenVMS usage: | logical name table
> type: | character-coded text string
> access: | read only
> mechanism: | by 32-bit or 64-bit descriptor (Alpha)
> mechanism: | by 32-bit descriptor (VAX)

> The table containing the logical name logical_name. Logical name tables are converted to uppercase. Unless your application requires an application-specific logical name table, this argument should be either the default ICC Registry search list (ICC$REGISTRY), or the default registry table (ICC$REGISTRY_TABLE).

> #### conn_event_rtn

> OpenVMS usage: | user_routine
> type: | procedure_entry_mask
> access: | call without stack unwinding
> mechanism: | by 32-bit or 64-bit linkage reference (Alpha)
> mechanism: | by 32-bit reference (VAX)

> The address of the AST routine to be called for incoming connect events. This routine will be called in the mode of the caller. (No mechanism is provided for the routine to be called at a different mode).

> You must have a conn_event_rtn to operate as a server.

> #### disc_event_rtn

> OpenVMS usage: | user_routine
> type: | procedure_entry_mask
> access: | call without stack unwinding
> mechanism: | by 32-bit or 64-bit linkage reference (Alpha)
> mechanism: | by 32-bit reference (VAX)

> The address of the AST routine to be called for incoming disconnect events. This routine will be called in the mode of the caller. (No mechanism is provided for the routine to be called at a different mode). The arguments, conn_event_rtn, and disc_event_rtn, may reference the same routine.

> #### recv_rtn

> OpenVMS usage: | user_routine
> type: | procedure_entry_mask
> access: | call without stack unwinding
> mechanism: | by 32-bit or 64-bit linkage reference (Alpha)
> mechanism: | by 32-bit reference (VAX)

> The address of the AST routine to be called for incoming new data events.

> If the user provides this routine, it indicates that the user will supply a buffer of the size required (specified in an argument to the recv_rtn at each call) each time one is requested. If the user supplies this routine, receive calls should only be issued after receive events arrive and sufficient buffer space has been allocated to handle the incoming data.

> This routine will be called in the mode of the caller. (No mechanism is provided for the routine to be called at a different mode).

> #### maxflowbufcnt

> OpenVMS usage: | longword_unsigned
> type: | longword (unsigned)
> access: | read only
> mechanism: | by value

> The maximum number of pending inbound messages (per connection) that ICC will allow the user before initiating flow control. A message is pending if it is being held within ICC but no receive call(s) are outstanding from the user.

> Default = 5 (Pass 0 to get the default)

> #### prot

> OpenVMS usage: | longword_unsigned
> type: | longword (unsigned)
> access: | read only
> mechanism: | by value

> This argument is ignored for non-server applications.

> The default protection scheme for this association is as follows:

> 0 - access for everyone (default)
> 1 - stops WORLD access
> 2 - stops both WORLD and GROUP access

> Advanced access control is provided by ICC Security objects. Refer to the OpenVMS System Manager's Manual for information on ICC system management and security.

### Description

> This service declares an application association with ICC. Servers must make this call to declare or register their name and to indicate their readiness to receive incoming connections. Although a client is permitted to call this routine, it is unnecessary for simple applications. A client application that wishes to be notified of disconnection events or Receive Data events must call the $ICC_OPEN_ASSOC service.

> A client can open a connection without specifying an open association; this automatically creates a default association name of ICC$PID_nnnnnnnn (where nnnnnnnn is a character representation of the Process ID).

> NETMBX privilege is required to open any association.

> The association name space is a controlled resource. Refer to the OpenVMS System Manager's Manual for information on managing this resource.

> An attempt to open an association with a name not authorized as described in the OpenVMS System Manager's Manual will fail with the error SS$_NOPRIV returned to the caller. In addition to making entries in the system's local association name space, a call to $ICC_OPEN_ASSOC may also make an entry in a simple clusterwide registry of active associations.

> An association may only be accessed from the mode in which it was opened. Inner modes are prevented from using the default association.

> An application can open any number of associations subject to available process BYTLM quota. Currently, there is a systemwide limit of 512 open associations. There is no limit imposed clusterwide.

> Description of User-Supplied Routines (ASTs)

> When opening an association, the user may optionally supply a connect/disconnect AST and/or a Data Event AST. These routines will be used for all connections established over the specified association. In addition, for any of the asynchronous services (those provided with both an immediate return and a "W" form), a completion AST may be supplied by the user. This section describes these ASTs.

> 1. Connect and Disconnect AST

> The user chooses the name of this routine and supplies the procedure name as an argument to the Open Association service. Seven arguments will be passed to the user.

> The first argument notifies the user whether this is an incoming new connection or a disconnection of an existing connection. The second identifies the connection. The third and fourth provide access to incoming connect or disconnect data (if any) sent by the cooperating application. The fifth argument provides the number of bytes available for any optional Accept or Reject data (in the case of a connect request) or the disconnect reason supplied by the cooperating application (if any).

> For connect events, the sixth and seventh arguments are the EPID and username of the process requesting the connect, respectively.

> The user has the choice of using and declaring a common routine or separate routines as specified when calling $OPEN_ASSOCIATION.

> Format

>     ConnDiscRtn  event_type ,conn_handle ,data_len ,data_bfr ,P5 ,P6 ,P7

> C Prototype:

>     void ConDiscRtn  (unsigned int event_type, unsigned int conn_handle,
>                       unsigned int data_len, char *data_bfr,
>                       unsigned int P5, unsigned int P6, char *P7);

> Arguments

>     event_type
>     Type:       longword (unsigned)
>     Access:     read only
>     Mechanism:  by value

> This field will contain a code describing the type of event. The possible event codes are defined in ICCDEF:

>     ICC$C_EV_CONNECT      - Connection event
>     ICC$C_EV_DISCONNECT   - Disconnection event

>     conn_handle
>     Type:       longword (unsigned)
>     Access:     read only
>     Mechanism:  by value

> The handle of the connection associated with the event.

>     data_len
>     Type:       longword (unsigned)
>     Access:     read only
>     Mechanism:  by value

> The length (in bytes) of the incoming data. This value specifies the length of the buffer data_bfr, and will be between 0 and 1000, with zero indicating no data.

>     data_bfr
>     Type:       character-coded text string
>     Access:     read only
>     Mechanism:  by 32-bit or 64-bit value (Alpha)
>                 by 32-bit value (VAX)

> The 32-bit address of the P1-space buffer containing the data, or zero if no data is available. The length of this buffer is specified by the argument data_len.

> Upon return from the AST, the address of the data is no longer valid. An application wishing to reference the Connection or Disconnection data after Return must copy the data from the supplied buffer to storage owned by the application.

>     P5
>     Type:       longword (unsigned)
>     Access:     read only
>     Mechanism:  by value

> The usage of this argument is dependent on the specified event type code (event_type).

> For connect events (event_type=ICC$C_EV_CONNECT), this argument contains the length (in bytes) of the buffer available for a reply.

> For disconnect events (event_type=ICC$C_EV_DISCONNECT), this argument contains the user-defined disconnect reason/status from the remote partner.

>     P6
>     Type:       longword (unsigned) (VAX), quadword (Alpha)
>     Access:     read only
>     Mechanism:  by value

> The usage of this argument is dependent on the specified event type code (event_type).

> For connect events (event_type=ICC$C_EV_CONNECT), this argument contains the EPID of the process requesting the connection, passed by value.

> For disconnect events (event_type=ICC$C_EV_DISCONNECT), this argument contains the user-defined user_context supplied when the connection was opened. For a client, the user_context is that supplied to the $ICC_CONNECT call. For a server, it is the value supplied to $ICC_ACCEPT.

>     P7
>     Type:       character-coded text string
>     Access:     read only
>     Mechanism:  by reference

> For connect events: Username, passed by reference (to P1 space buffer) as a 12-character, space-filled string.

> The application must copy this information to local storage before exiting from the connect routine.

> For disconnect events, this argument is zero (0).

> 2. Data Event Routine

> This routine, if supplied by the user when opening the association, allows the user to be notified of any pending data events over any connections subsequently opened over that association.

> If the user has supplied this routine, the Receive service must only be called in response to incoming data events signaled by this routine, and must be called with a buffer large enough to handle the message size specified.

> Use of this routine obligates the user to allocate buffers up to the size requested by the cooperating application. The only recovery provided at this time if a sufficiently large buffer cannot be allocated is to disconnect the connection. Failure to issue a receive call or disconnect may stall all further communication on this connection.

> Format

>     DataEventRtn  message_size ,conn_handle ,user_context

> C Prototype:

>     void DataEventRtn  (unsigned int message_size, unsigned int conn_handle,
>                         unsigned int user_context);

> Arguments

>     message_size
>     Type:       longword (unsigned)
>     Access:     read only
>     Mechanism:  by value

> This field will contain the number of bytes in the pending data event.

>     conn_handle
>     Type:       longword (unsigned)
>     Access:     read only
>     Mechanism:  by value

> The handle of the connection associated with the event. This value should be used as the conn_handle argument to $ICC_RECEIVE.

>     user_context
>     Type:       longword (unsigned) (VAX), quadword (Alpha)
>     Access:     read only
>     Mechanism:  by value

> The user-defined user_context supplied when the connection was opened. For a client, the user context is that supplied to the $ICC_CONNECT call. For a server, it is the value supplied to $ICC_ACCEPT.

> 3. Completion ASTs

> Completion ASTs may be supplied to the $ICC_CONNECT[W], $ICC_DISCONNECT[W], $ICC_TRANSMIT[W], $ICC_RECEIVE[W], $ICC_TRANSCEIVE[W], and $ICC_REPLY[W] services. In all cases, they are called at the completion of the requested operation, with the single argument, the AST parameter supplied when the original service was called, passed by value.

> Completion ASTs are not called if the service returns an error prior to initiating the operation. $ICC_CONNECT and $ICC_ACCEPT accept the flag ICC$V_SYNCH_MODE which indicates that the routines $ICC_TRANSMIT[W], $ICC_RECEIVE[W], and $ICC_REPLY[W] are permitted to return the status SS$_SYNCH, which will indicate that completion has already occurred and the AST will not be called.

> Required Access or Privileges

> Refer to the OpenVMS System Manager's Manual for more information.

> Required Quota

> BYTCNT, BYTLM

> Related Services

> $ICC_ACCEPT, $ICC_CLOSE_ASSOC, $ICC_CONNECT, $ICC_CONNECTW, $ICC_DISCONNECT, $ICC_DISCONNECTW, $ICC_RECEIVE, $ICC_RECEIVEW, $ICC_REJECT, $ICC_REPLY, $ICC_REPLYW, $ICC_TRANSCEIVE, $ICC_TRANSCEIVEW, $ICC_TRANSMIT, $ICC_TRANSMITW

### Condition Values Returned

> SS$_NORMAL | Normal completion.
> SS$_ACCVIO | Access violation on parameter.
> SS$_BADPARAM | Bad parameter value specified.
> SS$_DUPLNAM | Specified association name is already registered (already exists), or default association is already open.
> SS$_EXQUOTA | One or more process quotas has been exceeded (probably BYTCNT/BYTLM).
> SS$_INSFARG | Too few arguments supplied.
> SS$_INSFMEM | Not enough system resources or process virtual memory available.
> SS$_IVMODE | Attempt to open default association from other than user mode.
> SS$_NOLINKS | Too many associations open for this process.
> SS$_NONETMBX | Request requires NETMBX privilege.
> SS$_NOPRIV | No privilege for association name access or logical name table access if using the Registry.
> SS$_SSFAIL | Transport association name table is full, systemwide.
> SS$_TOO_MANY_ARGS | Too many arguments were specified. Any failures from the system services: $ENQ, $DEQ, $CRELNM, $TRNLNM.

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