Accessing a data file.

[Jesse Sanders]

I am working with one progran that dumps its results to a text file these results come from a piece of lab equipment that runs about 1 sample a minute.I want alpha 5 to look into this file everytime that a new set of results is added, and pull the new results into Aplha.
There are 2 ways I can think of doing this.
One is to pull the data every minute or so and look for new results.
The other is to watch the file and when it's size changes to go and get the new results.
Anyone had any experience doing anything like this?
I am open to any ideas.

[Robert Adler]

RE: Accessing a data file.

Jesse:

A5 can read the text file. But there are questions that arise before considering an approach.

1. Will both applications attempt to access the text file at the same time?
2. Does the lab machine create the file if it does not exist?
3. Would an empty file cause the lab machine any problems?

there are other points based on the above questions. the biggest problem is simultaneous access. What is the impact on the lab program?

A5 can read the file and return an empty file. this would be the cleanest approach.

I hope this helps.

bob adler

[Jesse]

RE: Accessing a data file.

Question 1 I have shared access to the file.
Question 2 The lab program can add data to a an empty file but I do not think it creates the file at the begining of the session.
Question 3 I do not know if the lab program holds a pointer to the end of th file or just looks for the end and adds the next record on at the end.

My problem is how do I set a script that runs in the background or responds to an action or the other program that retrieves the data in question.

[Tom Cone Jr]

RE: Accessing a data file.

Jesse, if it's ok for the current form to remain open continuously, you could use the form's Ontimer event to check and retrieve information from the text file.

In pseudo code something like this is what I have in mind:

1) retrieve text file; parse it; store the last results
2) store text file size in A5 variable
3) wait one minute
4) check text file size
5) if larger than the variable's value
6) goto 1
7) else
8) goto 3
9) end if

[infomatic]

RE: Accessing a data file.

Jesse;

Before doing anything I would
1.Rename the file that your device created
2.check if it actualy did rename by checking if the new file exists
3. copy an empty file back as the name of the origanal file name so that the device can drop more information.
4 when your done delte or archive your file (you must delete the file for the rename to work.

Good Luck