CODEWITHSUNDEEP
tcl
user3865874
user3865874

Reputation: 21

TCL open file and check for error

I am programming TCL for Cisco TCL/IVR inside voice gateway.

I have some text files with public holidays dates, which I need to open on the primary server. If an error is returned while opening the file, I want to try to use a secondary backup server.

code:

if [catch {set fd [open $filename] } errmsg] {
    error "Unable to open the file: $filename on Primary Server \n $errmsg"
    set filename $httpsvr2$textfile
    if [catch {set fd [open $filename] } errmsg] {
        error "Unable to open the file: $filename on Primary Server \n $errmsg"
        set Read 0
    }
    else {
        set Read 1
    }
}
else {
    set Read 1
}

I was trying to use the Read flag; if it is 1, then I will search inside the file. If it is 0, it's because the file couldn't be opened on any of the servers, so I will just treat the call as if it's a working (non-holiday) day.

However, in my current code when the first attempt to open the file fails, it automatically stops executing the script.

How could I continue executing after the first error? Should I make a procedure and return values like -1? If so, how could I do that?

Upvotes: 2

Views: 5623

Answers (2)

Jerry
Jerry

Reputation: 71598

The command error exits the script (meaning once error is reached, you could say that execution stops). You would probably be better off by putsing the error message through stderr or a more suitable channel:

puts stderr "Unable to open the file: $filename on Primary Server \n $errmsg"

Upvotes: 2

don_q
don_q

Reputation: 415

I would make it a procedure like you are thinking

proc openFils { filename httpsvr2 textfile ) {

    set fd -1
    foreach f $filename $httpsvr2$textfile {

        if { ! [file exists $f] } {
             puts stderr "File $f not on system"
        }

        if [catch {set fd [open $f] } errmsg] {
             puts stderr "Unable to open the file: $f \n $errmsg"
        } else {
             break
        }
    }

   return $fd
}

Now you can perform an operation on the file handle 'fd', note: the above script will open and return the first file it can, not both.

Upvotes: 0

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