TCL Opinions wanted – file reading/writing

[Anonymous]

I have an interface that I think I’m going to have to read/write to a file in the Xlate.  So I want my TCL doing the reading/writing as efficient as possible.

My question is:  Is it more efficient to use redirection, or to use the TCL file commands to do this?

Topic

[Anonymous]

Matt,

How do you mean redirection?

Greg

[Anonymous]

By using redirection, like:

exec ls > jml.txt

instead of tcl commands:

set fileid [open jml.txt w]

puts $fileid [exec ls]

close $fileid

[Anonymous]

I’m open to correction on this point but I believe that when you exec TCL creates a subprocess to contain the running program.  I assume this means a shell.  The file command executes directly from TCL so it should be faster.  If I have time I may test it…

Cheers,

[Richard Hart]

Matt.

I would be very surprised so find an ‘exec’ running quicker than ‘in-line’ code as the exec has to perform similar file ops AND start its own process.

If you are using files to read/write, be careful to ensure that a file is not being read at the same time it is written.

We use one ‘file’ interface and we timestamp the output file to the nearest hour.  The ‘read’ process runs an hour ‘behind’ to avoid conflict.

[Anonymous]

Your point is well taken.  Thank you both very much.

[Brad Dorr]

Matt,  in another discussion you mentioned that you have a WEB front end.  I am in the processes of doing that.  I have loaded Apache onto our Unix server.  I have created some simple cgi scripts to run a hciconnstatus command return the results.  I would like to be able to run a tcl script.  You mentioned that you called the tcl script from the cgi script how can you send me an example?

[Vamshi Mugu]

Hi Matt and Brad,

Please post the web stuff to the board. I am interested in it too.

thanks,

vamshi.

[Tom Patton]

I use the tcl file commands only because I want more control over how I open e.g. appends etc., and lock contention so I can handle the errors (if any).

[Author]

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