Re: When starting a process, at what point does "open()" return?

The open call will return when the process exits, if the process hangs and does not exit, then the open will not return unless you arrange for it to be interrupted early (such as by setting an alarm()).

Update: Doh! Of course open doesn't wait for the process to exit, how could you read from the pipe if it did? Apparently I need more sleep...

We're not surrounded, we're in a target-rich environment!

Comment on Re: When starting a process, at what point does "open()" return?

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Re: Re: When starting a process, at what point does "open()" return? by esh (Pilgrim) on Aug 18, 2003 at 02:25 UTC
The open call will return when the process exits This is not true on operating systems I'm familiar with and I doubt it's true on Windows, either. The open call returns when the process starts not when it exits. You can then have the child process talking with the parent process while both are running at the same time. Here's proof: `perl -e 'open F, "sleep 60 \|" or die "$!\n"; print "done\n"'` [download] I know that "sleep 60" takes about 60 seconds to run, but my top perl program prints "done" right away and exits. It does not wait for the "sleep 60" to exit. The related system call does wait for the child return when the child process exits. -- Eric Hammond	[reply] [d/l]
Re: Re: When starting a process, at what point does "open()" return? by Anonymous Monk on Aug 18, 2003 at 02:22 UTC
That's not how it works. If it worked that way, you could never read from a subprocess or write to it.	[reply]