how can we capture the exit code correctly when we call a command via 'system'? from the testcase below i consistently capture "-1" which the expectation is "0" for code1 and "1" for code2.
test1.pl
use feature qw(say);
use strict;
my $code = system("./test2.pl 0");
say "code1 = $code";
system("./test2.pl 0");
say "code1' = $?";
$code = system("./test2.pl 1");
say "code2 = $code";
system("./test2.pl 1");
say "code2' = $?";
test2.pl
use feature qw(say);
use strict;
say "arg = @ARGV[0]";
my $exit_code = @ARGV[0];
say "this is a dummy script which exit with $exit_code";
exit $exit_code;
Output:
% ./project_r/test.pl
code1 = -1
code1' = -1
code2 = -1
code2' = -1
As per the documentation for system
, -1
indicates there was a problem trying to execute the command, and that the error message is found in $!
.
system(...);
die("Can't run test2: $!\n") if $? == -1;
die("test2 killed by signal ".( $? & 0x7F )."\n") if $? & 0x7F;
die("test2 exited with error ".( $? >> 8 )."\n") if $? >> 8;
say("Child completed successfully.");
As you can see by the lack of output of this is a dummy
, your program never ran.
Likely culprits are:
A missing shebang ( #!
) line could render a file non-executable, but I'm presuming you simply left out the shebang lines from your snippets for conciseness (since ./project_r/test.pl
wouldn't run otherwise).
I'm also assuming that the difference in the name of the file you posted ( test1.pl
) and the file you executed ( test.pl
) isn't relevant.
My best guess is that test2.pl
is in the same directory as test.pl
/ test1.pl
, which isn't the current directory but a subdircetory of the current directory named project_r
.
Fix:
use FindBin qw( $RealBin );
my $code = system("$RealBin/test2.pl", "0");
Note that if you are going to run other Perl programs from a Perl program, you need to use the same settings. Otherwise you might run into situations where you are using a different perl
with your parent perl
's settings:
Your current Perl is in $^X
:
system $^X, 'test2.pl', '0';
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