The system function doc it contains some chunks of code that you could put directly into a subroutine:
@args = ("command", "arg1", "arg2");
system(@args) == 0
or die "system @args failed: $?"
You can check all the failure possibilities by inspecti
+ng $?
like this:
if ($? == -1) {
print "failed to execute: $!\n";
}
elsif ($? & 127) {
printf "child died with signal %d, %s coredump\
+n",
($? & 127), ($? & 128) ? 'with' : 'without
+';
}
else {
printf "child exited with value %d\n", $? >> 8;
}
Update: I adapted it for a program of mine this way:
#!/usr/bin/perl
use strict ;
use warnings ;
use Carp ;
# some code here
sub check_cmd {
my %parms = @_ ;
croak "No commands" unless
exists $parms{cmd} and ref($parms{cmd}) eq 'ARRAY' ;
my @cmd = @{$parms{cmd}} ;
$parms{onerror} = 'croak' unless exists $parms{onerror} ;
$parms{onerror} = lc $parms{onerror} ;
$parms{onerror} = 'croak' unless $parms{onerror} =~ /^(croak|carp|no
+ne)$/ ;
$parms{errormsg} = "@cmd failed" unless exists $parms{errormsg} ;
my $result = system(@cmd) ;
unless ($result == 0) {
print STDERR $parms{errormsg} ;
croak report_error($?,$!) if $parms{onerror} eq 'croak' ;
if ($parms{onerror} eq 'carp') {
carp report_error($?,$!) ;
print STDERR "Press ENTER" ;
scalar <STDIN> ;
}
}
return $result >> 8 ; # exit value
}
sub report_error {
my ($syserr,$message) = @_ ;
my $signal = $syserr & 127 ;
my $exitvalue = $syserr >> 8 ;
my $error ;
if ($syserr == -1) {
$error = "failed to execute: $message" ;
} elsif ($signal) {
$error = "program died with signal $signal" ;
}
return $error ;
}
The subroutine was called like this:
$ret = check_cmd(cmd => [$config{cvs_command},'login'],
onerror => 'none',
errormsg => "cvs login failed") ;
unless ($ret == 0) {
# do something...
}
I hope this helps a bit
Ciao! --bronto
The very nature of Perl to be like natural language--inconsistant and full of dwim and special cases--makes it impossible to know it all without simply memorizing the documentation (which is not complete or totally correct anyway).
--John M. Dlugosz
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