Quoth Jack <
[email protected]>:
<snip: some sort of persistant shared memory>
Well, on systems that support it you can use SysV shared memory, for
which Perl natively has the raw shm* calls. This doesn't work on
Windows, though.
You could try IPC::Shareable for Unix and Win32::MMF::Shareable (which
has the same interface) for Win32, which provide an easier interface to
shared memory.
Another alternative would be mmap, using the Sys::MMap module. mmap is
substantially better behaved than SysV shm, and portable to Windows.
In what sense then is this memory 'persistent'? I think you are rather
confused about what is and isn't possible under modern operating
systems: unless you take steps to prevent it, all memory allocated by a
process is released when that process exits. This is a feature
.
Ben
ok.. lets talk with code - I got this to work with DB_File.. my
fundamental question is, once you create the tied hash like the below,
and the program is done executing, how do I access the hash and query
it from another Perl execution program ?? I tried using the API
interface afterwards as described here
http://perldoc.perl.org/DB_File.html
, see the error at bottom:
### RUN PROGRAM 1 #####
use warnings ;
use strict ;
use DB_File ;
our (%h, $k, $v) ; unlink "fruit" ;
tie %h, "DB_File", "fruit", O_RDWR|O_CREAT, 0666, $DB_HASH
or die "Cannot open file 'fruit': $!\n"; # Add a few key/
value pairs to the file
$h{"apple"} = "red" ;
$h{"orange"} = "orange" ;
$h{"banana"} = "yellow" ;
$h{"tomato"} = "red" ; # Check for existence of a key
print "Banana Exists\n\n" if $h{"banana"} ; # Delete a key/
value pair.
delete $h{"apple"} ; # print the contents of the file
while (($k, $v) = each %h)
{ print "$k -> $v\n" }
untie %h ;
#####START SEPARATE PROGRAM 2 ###
use warnings ;
use strict ;
use DB_File ;
$db = tie %h, "DB_File", "testfile1" ;
foreach (keys %h)
{ print "$_\n" }
### PROGRAM 2 ERRORS:
Global symbol "$db" requires explicit package name at
test_dbfile1_query.pl .
Global symbol "%h" requires explicit package name at
test_dbfile1_query.pl .
Global symbol "%h" requires explicit package name at
test_dbfile1_query.pl 5.
Execution of test_dbfile1_query.pl aborted due to compilation errors.
