Invokes and interacts with DDE services
Syntax
$DDEFunction ( p1, p2, p3, p4, ... )
Parameters
| p1 | return type, longint |
| p2 | command, longint |
| p3 | server handle, longint |
| p4 | application command, string |
Comments
Where p1, p2, and so on, indicate the desired DDE service and the data required by that service. The first parameter, p1, is entirely for Zim’s benefit and defines the data type of the value returned by the DDE service. The second parameter, p2, determines the desired service and the remaining parameters are used by the DDE service itself.
The first parameter, p1, is dependent on the DDE service you invoke and the application with which you are communicating. When using $DDEFunction, specify p1 in such way that sufficient space is allocated for the return value. For example, if you use $DDEFunction to invoke a DDE service that returns a long integer result, then the p1 you provide must be of type longint as well. If p1 were of type char 10, $DDEFunction would expect a result value of up to 10 characters in length.
The second parameter, p2, is a number that indicates the DDE service to invoke. The possible values for p2 are shown in the table below. The p2 parameter must be of type longint or int.
| DDE Service | p2 Value | Description |
| CONNECT | 1 | Start a conversation with an application and topic. |
| POKE | 2 | Set an item to a value. |
| DISCONNECT | 3 | Terminate a conversation. |
| PEEK | 4 | Retrieve the value of an Item. |
| EXECUTE | 5 | Execute an application. |
The remaining parameters, p3, p4, and so on, are dependent on the DDE service you invoke and the application with which you are communicating.
See Also
About DDE Services
DDEExecute
Send commands and macros to the target application.
Syntax
procedure DDEExecute (out tErrCode, inout tServ,
in app_cmd)
Parameters
| tErrCode | longint, an error code |
| tServ | longint, connection handle |
| app_cmd | char, command or macro to be executed |
Comments
DDEExecute sends target application specific commands and macros to be executed by the remote application. Consult the documentation of the remote application for information on these commands.
The filename is ddeexec.pgm.
Example
For example, given that DDE_Err and hServ are of type longint and that hServ has been set by a previous call to DDEConnect, to send the ‘[NEW(1)]” command to EXCEL
DDEExecute(DDE_Err, hServ, ‘[NEW(1)]’)
instructs EXCEL to open a new spreadsheet.
DDEPoke
Assigns a value to a specific item in a remote application.
Syntax
procedure DDEPoke (out tErrCode, inout tServ,
in dde_item, in dde_val)
Parameters
| tErrCode | longint, an error code |
| tServ | longint, connection handle |
| dde_item | char, item name |
| dde_val | char, value of the item |
Comments
DDEPoke assigns a value to a specific item in a remote application. Consult the documentation of the remote application for information on what constitutes an item. The value of an item is always given as char.
The filename is ddepoke.pgm.
Example
For example, given that DDE_Err and hServ are of type longint, to set the value of row 1, column 1 in the current spreadsheet, enter the following:
DDEPoke (DDE_Err, hServ, ‘R1C1′, ’25’)
This example “pokes” the value ’25’ into row 1, column 1.
DDEPeek
Syntax
procedure DDEPeek (out tErrCode, inout tServ, in dde_item, out dde_val)
Parameters
| tErrCode | longint, an error code |
| tServ | longint, connection handle |
| dde_item | char, item name |
| dde_val | char, value of the returned item. Must be a string at least five characters in length |
Comments
DDEPeek retrieves the value of a specific item from a remote application. Consult the documentation of the remote application for information on what constitutes an item. The value of an item is always returned as char.
The filename is ddepeek.pgm.
Example
For example, given that DDE_Err and hServ are of type longint, that DDE_OutValue is of type alpha and is 10 characters long, and that hServ has been set in a previous call to DDEConnect, to retrieve the value of row 1, column 1 in the current spreadsheet, enter the following:
DDEPeek(DDE_Err, hServ, ‘R1C1’, DDE_OutValue)
This example “peeks” at the value of the cell at row 1, column 1 and places the retrieved value in DDE_OutValue.
DDEConnect
Sets up the access to the remote application.
Syntax
DDEConnect ( out tErrCode,
out tServ,
in dde_app,
in dde_topic)
Parameters
| tErrCode | A returned error code. It must be a longint. |
| tServ | The returned connection handle. It also must be a longint. |
| dde_app | A string containing the application name. |
| dde_topic | A string containing the topic name. |
Comments
The procedure is supplied with the application name and topic name (usually the document name). DDEConnect assigns a connect handle to the “tServ” variable to be used in subsequent commands. DDEConnect is compiled.
The filename is ddeconn.pgm.
Example
For example, given that DDE_Err and hServ are of type longint:
DDEConnect (DDE_Err, hServ, ‘excel’, ‘sheet1’)
starts a conversation with Microsoft EXCEL. The topic of the conversation is the spreadsheet ‘sheet1’. In this case, EXCEL must be started and ‘sheet1’ opened beforehand.
DDEDisconnect
Terminate access to the remote application.
Syntax
procedure DDEDisconnect (out tErrCode, inout tServ)
Parameters
| tErrCode | longint, an error code |
| tServ | longint, connection handle |
Comments
DDEDisconnect terminates the access to the remote application.
The filename is ddedisc.pgm.
Example
For example, given that DDE_Err and hServ are of type longint and that hServ has been set by a previous call to DDEConnect, enter the following to terminate a DDE conversation:
DDEDisconnect (DDE_Err, hServ)
This example ends a conversation previously established using the CONNECT service.
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