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Re^2: System call + signals = bad return code?

by swkronenfeld (Hermit)
on Sep 28, 2007 at 22:30 UTC ( #641628=note: print w/replies, xml ) Need Help??


in reply to Re: System call + signals = bad return code?
in thread System call + signals = bad return code?

I think I'm being unclear in my original post. I don't want the child to receive the signal, nor am I using this alarm as a timeout to make sure the system call doesn't hang.

In the real code, a connection to MySQL is established via the DBI module. Then a wget command is issued that takes a long time. During that time, the database connection times out, and must send a signal to the parent. This causes $? and $! to be set. But in addition to those, the system('wget') call returns -1. I know the wget succeeds, because the file is completely downloaded. But since system() returns -1, it looks like the wget failed!
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Re^3: System call + signals = bad return code?
by bluto (Curate) on Sep 28, 2007 at 23:00 UTC
    I was confused by your example. Sorry. This statement though still holds: I've seen similar cases where system returns an invalid result if I've already forked off an unrelated process and it happens to die when system() is executing. (i.e. in addition to signals, process reaping is problematic). You may want to try replacing system() with fork/exec/waitpid. The waitpid will return the status for the child pid you pass to it.

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