CODEWITHSUNDEEP
linuxperlunixfork
IDDQD
IDDQD

Reputation: 3751

One variable shared across all forked instances?

I have a Perl script that forks itself repeatedly. I wish to gather statistics about each forked instance: whether it passed or failed and how many instances there were in total. For this task, is there a way to create a variable that is shared across all instances?

My perl version is v5.8.8.

Upvotes: 1

Views: 97

Answers (2)

pilcrow
pilcrow

Reputation: 58711

IPC::Shareable does what you literally ask for. Each process will have to take care to lock and unlock a shared hash (for example), but the data will appear to be shared across processes.

However, ordinary UNIX facilities provide easier ways (IMHO) of collecting worker status and count. Have every process write ($| = 1) "ok\n" or "not ok\n" when it END{}s, for example, and make sure that they are writing to a FIFO as comparatively short writes will not be interleaved. Then capture that output (e.g., ./my-script.pl | tee /tmp/my.log) and you're done. Another approach would have them record their status in simple files — open(my $status, '>', "./status.$$") — in a directory specially prepared for this.

Upvotes: 2

Alexander L. Belikoff
Alexander L. Belikoff

Reputation: 5721

You should use IPC in some shape or form, most typically a shared memory segment with a semaphore guarding access to it. Alternatively, you could use some kind of hybrid memory/disk database where access API would handle concurrent access for you but this might be an overkill. Finally, you could use a file with record locking.

Upvotes: 2

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