How to make perl exit with an error code upon use of uninitialized-value?












0















I don't see how to make perl fail upon use of uninitialized-value. Is there a way to make this the default behavior? Thanks.



https://perlmaven.com/use-of-uninitialized-value






perl







share|improve this question


















  • 2





    What have you tried so far? You didn't include any code, so it's impossible to know. Also, take a look at exit.

    – Matt Jacob
    Nov 22 '18 at 3:51











  • I don’t know what to try. I want the program to fail instead of just giving a warning. This must be done with some kind of configuration of Perl at the beginning of a script. Exit won’t work.

    – user1424739
    Nov 22 '18 at 4:04






  • 1





    Please edit your question and include the code you're claiming isn't working.

    – Matt Jacob
    Nov 22 '18 at 4:05






  • 6





    perldoc.perl.org/warnings.html#Fatal-Warnings

    – Shawn
    Nov 22 '18 at 4:14











  • The link from @Shawn seems to be what you want. But also see Carp::Always

    – zdim
    Nov 22 '18 at 6:10
















0















I don't see how to make perl fail upon use of uninitialized-value. Is there a way to make this the default behavior? Thanks.



https://perlmaven.com/use-of-uninitialized-value






perl







share|improve this question


















  • 2





    What have you tried so far? You didn't include any code, so it's impossible to know. Also, take a look at exit.

    – Matt Jacob
    Nov 22 '18 at 3:51











  • I don’t know what to try. I want the program to fail instead of just giving a warning. This must be done with some kind of configuration of Perl at the beginning of a script. Exit won’t work.

    – user1424739
    Nov 22 '18 at 4:04






  • 1





    Please edit your question and include the code you're claiming isn't working.

    – Matt Jacob
    Nov 22 '18 at 4:05






  • 6





    perldoc.perl.org/warnings.html#Fatal-Warnings

    – Shawn
    Nov 22 '18 at 4:14











  • The link from @Shawn seems to be what you want. But also see Carp::Always

    – zdim
    Nov 22 '18 at 6:10














0












0








0








I don't see how to make perl fail upon use of uninitialized-value. Is there a way to make this the default behavior? Thanks.



https://perlmaven.com/use-of-uninitialized-value






perl







share|improve this question














I don't see how to make perl fail upon use of uninitialized-value. Is there a way to make this the default behavior? Thanks.



https://perlmaven.com/use-of-uninitialized-value






perl




perl






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Nov 22 '18 at 3:39









user1424739user1424739

1,11931627




1,11931627








  • 2





    What have you tried so far? You didn't include any code, so it's impossible to know. Also, take a look at exit.

    – Matt Jacob
    Nov 22 '18 at 3:51











  • I don’t know what to try. I want the program to fail instead of just giving a warning. This must be done with some kind of configuration of Perl at the beginning of a script. Exit won’t work.

    – user1424739
    Nov 22 '18 at 4:04






  • 1





    Please edit your question and include the code you're claiming isn't working.

    – Matt Jacob
    Nov 22 '18 at 4:05






  • 6





    perldoc.perl.org/warnings.html#Fatal-Warnings

    – Shawn
    Nov 22 '18 at 4:14











  • The link from @Shawn seems to be what you want. But also see Carp::Always

    – zdim
    Nov 22 '18 at 6:10














  • 2





    What have you tried so far? You didn't include any code, so it's impossible to know. Also, take a look at exit.

    – Matt Jacob
    Nov 22 '18 at 3:51











  • I don’t know what to try. I want the program to fail instead of just giving a warning. This must be done with some kind of configuration of Perl at the beginning of a script. Exit won’t work.

    – user1424739
    Nov 22 '18 at 4:04






  • 1





    Please edit your question and include the code you're claiming isn't working.

    – Matt Jacob
    Nov 22 '18 at 4:05






  • 6





    perldoc.perl.org/warnings.html#Fatal-Warnings

    – Shawn
    Nov 22 '18 at 4:14











  • The link from @Shawn seems to be what you want. But also see Carp::Always

    – zdim
    Nov 22 '18 at 6:10








2




2





What have you tried so far? You didn't include any code, so it's impossible to know. Also, take a look at exit.

– Matt Jacob
Nov 22 '18 at 3:51





What have you tried so far? You didn't include any code, so it's impossible to know. Also, take a look at exit.

– Matt Jacob
Nov 22 '18 at 3:51













I don’t know what to try. I want the program to fail instead of just giving a warning. This must be done with some kind of configuration of Perl at the beginning of a script. Exit won’t work.

– user1424739
Nov 22 '18 at 4:04





I don’t know what to try. I want the program to fail instead of just giving a warning. This must be done with some kind of configuration of Perl at the beginning of a script. Exit won’t work.

– user1424739
Nov 22 '18 at 4:04




1




1





Please edit your question and include the code you're claiming isn't working.

– Matt Jacob
Nov 22 '18 at 4:05





Please edit your question and include the code you're claiming isn't working.

– Matt Jacob
Nov 22 '18 at 4:05




6




6





perldoc.perl.org/warnings.html#Fatal-Warnings

– Shawn
Nov 22 '18 at 4:14





perldoc.perl.org/warnings.html#Fatal-Warnings

– Shawn
Nov 22 '18 at 4:14













The link from @Shawn seems to be what you want. But also see Carp::Always

– zdim
Nov 22 '18 at 6:10





The link from @Shawn seems to be what you want. But also see Carp::Always

– zdim
Nov 22 '18 at 6:10












2 Answers
2






active

oldest

votes


















2














Something like this perhaps:



#!/usr/bin/perl

use strict;

use warnings;

use warnings FATAL => qw[uninitialized];

use feature 'say';



my $foo;



say "Foo is $foo";

say "Don't get here";


Comment out the FATAL line to see the standard behaviour.






share|improve this answer































    0














    Dave's answer sure is the best pick for the described use case.



    Here is another solution, that demonstrates the use of the warning signal handler (see http://perldoc.perl.org/functions/warn.html).



    The benefit of using a signal handler is flexibility : you can trap any kind of warning, analyze it and then implement any behavior you like. In the given use case this is an overkill, it but can be useful in more complex cases.



    use strict;
    
use warnings;
    
use feature "say";
    

    
local $SIG{__WARN__} = sub {
    
    if ($_[0] =~ /^Use of uninitialized value/) {
    
        die $_[0]; 
    
    } else { 
    
        warn $_[0] ;
    
    }
    
};
    

    
my $foo;
    
say "Foo is $foo";
    
say "Dont get here";





    share|improve this answer























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      2 Answers
      2






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      2 Answers
      2






      active

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      2














      Something like this perhaps:



      #!/usr/bin/perl
      
use strict;
      
use warnings;
      
use warnings FATAL => qw[uninitialized];
      
use feature 'say';
      

      
my $foo;
      

      
say "Foo is $foo";
      
say "Don't get here";


      Comment out the FATAL line to see the standard behaviour.






      share|improve this answer




























        2














        Something like this perhaps:



        #!/usr/bin/perl
        
use strict;
        
use warnings;
        
use warnings FATAL => qw[uninitialized];
        
use feature 'say';
        

        
my $foo;
        

        
say "Foo is $foo";
        
say "Don't get here";


        Comment out the FATAL line to see the standard behaviour.






        share|improve this answer


























          2












          2








          2







          Something like this perhaps:



          #!/usr/bin/perl
          
use strict;
          
use warnings;
          
use warnings FATAL => qw[uninitialized];
          
use feature 'say';
          

          
my $foo;
          

          
say "Foo is $foo";
          
say "Don't get here";


          Comment out the FATAL line to see the standard behaviour.






          share|improve this answer













          Something like this perhaps:



          #!/usr/bin/perl
          
use strict;
          
use warnings;
          
use warnings FATAL => qw[uninitialized];
          
use feature 'say';
          

          
my $foo;
          

          
say "Foo is $foo";
          
say "Don't get here";


          Comment out the FATAL line to see the standard behaviour.







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 22 '18 at 9:34









          Dave CrossDave Cross

          47.7k34079




          47.7k34079

























              0














              Dave's answer sure is the best pick for the described use case.



              Here is another solution, that demonstrates the use of the warning signal handler (see http://perldoc.perl.org/functions/warn.html).



              The benefit of using a signal handler is flexibility : you can trap any kind of warning, analyze it and then implement any behavior you like. In the given use case this is an overkill, it but can be useful in more complex cases.



              use strict;
              
use warnings;
              
use feature "say";
              

              
local $SIG{__WARN__} = sub {
              
    if ($_[0] =~ /^Use of uninitialized value/) {
              
        die $_[0]; 
              
    } else { 
              
        warn $_[0] ;
              
    }
              
};
              

              
my $foo;
              
say "Foo is $foo";
              
say "Dont get here";





              share|improve this answer




























                0














                Dave's answer sure is the best pick for the described use case.



                Here is another solution, that demonstrates the use of the warning signal handler (see http://perldoc.perl.org/functions/warn.html).



                The benefit of using a signal handler is flexibility : you can trap any kind of warning, analyze it and then implement any behavior you like. In the given use case this is an overkill, it but can be useful in more complex cases.



                use strict;
                
use warnings;
                
use feature "say";
                

                
local $SIG{__WARN__} = sub {
                
    if ($_[0] =~ /^Use of uninitialized value/) {
                
        die $_[0]; 
                
    } else { 
                
        warn $_[0] ;
                
    }
                
};
                

                
my $foo;
                
say "Foo is $foo";
                
say "Dont get here";





                share|improve this answer


























                  0












                  0








                  0







                  Dave's answer sure is the best pick for the described use case.



                  Here is another solution, that demonstrates the use of the warning signal handler (see http://perldoc.perl.org/functions/warn.html).



                  The benefit of using a signal handler is flexibility : you can trap any kind of warning, analyze it and then implement any behavior you like. In the given use case this is an overkill, it but can be useful in more complex cases.



                  use strict;
                  
use warnings;
                  
use feature "say";
                  

                  
local $SIG{__WARN__} = sub {
                  
    if ($_[0] =~ /^Use of uninitialized value/) {
                  
        die $_[0]; 
                  
    } else { 
                  
        warn $_[0] ;
                  
    }
                  
};
                  

                  
my $foo;
                  
say "Foo is $foo";
                  
say "Dont get here";





                  share|improve this answer













                  Dave's answer sure is the best pick for the described use case.



                  Here is another solution, that demonstrates the use of the warning signal handler (see http://perldoc.perl.org/functions/warn.html).



                  The benefit of using a signal handler is flexibility : you can trap any kind of warning, analyze it and then implement any behavior you like. In the given use case this is an overkill, it but can be useful in more complex cases.



                  use strict;
                  
use warnings;
                  
use feature "say";
                  

                  
local $SIG{__WARN__} = sub {
                  
    if ($_[0] =~ /^Use of uninitialized value/) {
                  
        die $_[0]; 
                  
    } else { 
                  
        warn $_[0] ;
                  
    }
                  
};
                  

                  
my $foo;
                  
say "Foo is $foo";
                  
say "Dont get here";






                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered Nov 22 '18 at 20:57









                  GMBGMB

                  13.6k2824




                  13.6k2824






























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