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problem in error handling.

ajitnavasare
Novice

Nov 20, 2009, 4:15 AM

Post #1 of 5 (440 views)

problem in error handling.	Can't Post

I have a problem in error handling.

I want to stop the script as soon as it get an error and stop further execution.
In my below “sample script”, step 1 throws an error, and still step 2 get executed.
Can any one help me out, I want to do it in the following manner.
As on step 1 get error I want to stop the execution of script.

i think i am not using(or not aware of ) proper perl error handling features Unimpressed

Sample Script :
### Script : Start
use strict;
use warnings;
use Sys::HostIP;
use Win32::GuiTest qw[:ALL];
eval
{
system("start c:\\windows\\system32\\cmd1212.exe"); ### step 1
SendKeys(" dir {ENTER}"); ### Step 2
sleep 3;
};
if($@)
{
print "$@"
}
### Script : End
Thanks in Advance.

toolic
User

Nov 20, 2009, 5:48 AM

Post #2 of 5 (437 views)

Re: [ajitnavasare] problem in error handling. [In reply to]	Can't Post

If you want your program to die if the system call returns an error, you should not put the system inside the eval block. Also,
use die:

Code

system("start c:\\windows\\system32\\cmd1212.exe") and die "some useful message";

I updated my untested code above due to FishMonger's astute observation.

Code

perldoc -f system 
perldoc -f eval 
perldoc -f die

(This post was edited by toolic on Nov 20, 2009, 6:01 AM)

FishMonger
Veteran

Nov 20, 2009, 5:57 AM

Post #3 of 5 (433 views)

Re: [toolic] problem in error handling. [In reply to]	Can't Post

In Reply To

If you want your program to die if the system call returns an error, you should not put the system inside the eval block. Also,
use die:

Code

system("start c:\\windows\\system32\\cmd1212.exe") or die "some useful message";

Code

perldoc -f system 
perldoc -f eval 
perldoc -f die

The system function will return the exit code of the command, which is 0 on success. So the proper error handling would be along the lines of:

Code

system("start c:\\windows\\system32\\cmd1212.exe") == 0 or die "some useful message";

7stud
Enthusiast

Nov 20, 2009, 6:01 AM

Post #4 of 5 (430 views)

Re: [toolic] problem in error handling. [In reply to]	Can't Post

Can system() cause an error?

FishMonger
Veteran

Nov 20, 2009, 6:13 AM

Post #5 of 5 (426 views)

Re: [7stud] problem in error handling. [In reply to]	Can't Post

In Reply To

Can system() cause an error?

Since system is a built-in function, if it "causes" an error, then your Perl installation is corrupt.

The adjustment I made compares the return code of the system call to 0 and if they are not equal, then the command being executed failed, not Perl's system function.

See `perldoc -f system`
http://perldoc.perl.org/functions/system.html

(This post was edited by FishMonger on Nov 20, 2009, 6:14 AM)

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