Perl/Tk System Function Error

perl.j has asked for the wisdom of the Perl Monks concerning the following question:

I am making an "all-in-one calculator" (I guess). Here is my code (I know I do not have all subroutines defined, I'm still working on this as you can see):

use 5.12.4;
use warnings;
use Tk;

##### Create MainWindow #####
my $button_menu = new MainWindow;
#############################

##### MainWindow Buttons#####
my $calculator_button = $button_menu->Button(-text=>"Calculator",
                                         -width=>10,
                         -relief=> 'raised',
                             -command=>\&open_calculator)->pack();

my $formulas_button = $button_menu->Button(-text=>"Formulas",
                                       -width=>10,
                       -relief=> 'raised',
                       -command=>\&open_formulas)->pack();

my $lcf_button = $button_menu->Button(-text=>"Find LCF",
                                  -width=>10,
                      -relief=> 'raised',
                      -command=>\&open_lcf)->pack();

my $gcf_button = $button_menu->Button(-text=>"Find GCF",
                                  -width=>10,
                      -relief=> 'raised',
                      -command=>\&open_gcf)->pack();
#############################
sub open_calculator{
    system(qq{start "C:\\Windows\\system32\\calc.exe"});
}

MainLoop;
[download]

Why does the system function not open the Windows calculator? Also, is there any source code I could use to make a basic calculator in Tk?

Thanks!

--perl.j

Comment on Perl/Tk System Function Error Download Code

Replies are listed 'Best First'.
Re: Perl/Tk System Function Error by keszler (Priest) on Nov 18, 2011 at 01:07 UTC
On my XP system, removing the double-quotes makes it run calc. With the double-quotes I get a command window. Not sure why, but `system(qq{start C:\\Windows\\system32\\calc.exe});` [download] is the way to go. The same behavior occurs at the command prompt: with quotes, cmd window; without, calc.	[reply] [d/l]
Re^2: Perl/Tk System Function Error by afoken (Chancellor) on Nov 18, 2011 at 10:20 UTC
removing the double-quotes makes it run [...] Not sure why Simple: The first argument of the start command, when put in double quotes, is taken as the requested window title. If you need to quote the command to be started, you also need to provide a dummy window title, i.e.: `system('start "" "C:\\program files\\my application\\kaboom.exe" /foo +/bar');` [download] Also note that `system()` has a special case on Windows to run a program (with arguments) without waiting for it, and without having to mess with any shell or the braindead `start` program. This is documented in perlport: `system(1,'C:\\program files\\my application\\kaboom.exe','/foo','/bar' +); # ^-- the 1 is the special case for Windows` [download] Alexander -- Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)	[reply] [d/l] [select]
Re^2: Perl/Tk System Function Error by Anonymous Monk on Nov 18, 2011 at 09:07 UTC
Because you, like many, have not read "help start" or "help cmd" I use Proc::Background	[reply]
Re^2: Perl/Tk System Function Error by perl.j (Pilgrim) on Nov 18, 2011 at 01:10 UTC
It works! Thanks! --perl.j	[reply]
Re: Perl/Tk System Function Error by zentara (Archbishop) on Nov 18, 2011 at 12:32 UTC
is there any source code I could use to make a basic calculator in Tk? See Tk Virtual Keyboard. Also running the system command from a Tk program, will totally block the Tk eventloop until the system call returns, but it may work in your special case, as the eventloop should resume after the calculator window is closed. I'm not really a human, but I play one on earth. Old Perl Programmer Haiku ................... flash japh	[reply]

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