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[DDE] Tag
Dynamic Data Exchange
Format
OPEN (chan[,fileopt])"[DDE]dde_app;params"
Where:
[DDE]
File tag clause to inform ProvideX that it will be opening an external
Dynamic Data Exchange (DDE) application.
chan
Channel or logical file number to open.
dde_app
Path and/or name of DDE application; e.g., Excel. String expression.
fileopt
File options.
params
Optional DDE-specific parameters. Semicolon-separated arguments
and/or variables to receive returned values, etc. (Early implementations
of ProvideX used a vertical bar instead of a semicolon as separator --
both are now acceptable).
Please refer to the documentation supplied with the individual
product or application to determine how to communicate with it
using the [DDE] link.
Note: For use in WindX or Windows only.
Description
The [DDE] tag is used as a prefix in an OPEN statement to denote that ProvideX is to
route all file I/O requests to an external DDE application; e.g., Excel. ProvideX
recognizes the tag and deals with it internally at run time.
You can associate a CTL value with an item in a DDE application to have ProvideX
generate the CTL value automatically whenever the value of the associated item
changes; e.g,
0010 DEFCTL (dde_fileno)"item"=ctl_event
Troubleshooting
In the event that the DDE server is unavailable, ProvideX will attempt to start the
application and establish a DDE connection to it. The following paths are used to
locate the application:
· Directory from which the application loaded
· Current directory
· Windows system directory
· Windows directory
· All directories listed in the PATH environment variable.
If these search rules cannot locate the application, then an Error #10: Illegal
pathname specified will be reported, and MSG(-1) will contain text similar to
"DdeConnect Failed (err/ret=2/16394)."