Re^3: Daemon, log4perl & stderr/stdout

You need to make sure fileno(STDERR) is equal to 2.

fileno()==0 will be used as the child's STDIN.
fileno()==1 will be used as the child's STDOUT.
fileno()==2 will be used as the child's STDERR.

The above will allow you to redirect STDERR to a file, but system file handles (as opposed to Perl file handles) can't be redirected to a Perl function (such as the log4perl handler). If you wish to do that, you'll have to use a temporary file, IPC::Open3 or something like pc88mxer's code.

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Re^4: Daemon, log4perl & stderr/stdout by pc88mxer (Vicar) on May 27, 2008 at 23:17 UTC
This is a good point. If you don't explicitly `close(STDERR)`, it should stay at file descriptor 2 when you re-open it. For example: `close(STDIN); close(STDERR); open(STDERR, ">/tmp/foo"); print fileno(STDERR), "\n"; # prints 0` [download] However, if the `close(STDERR)` call is removed, `STDERR` remains at file descriptor 2. A quick test of `Proc::Daemon` indicates that `STDIN`, `STDOUT` and `STDERR` all have the expected file descriptors.	[reply] [d/l] [select]

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Re^4: Daemon, log4perl & stderr/stdout
by pc88mxer (Vicar) on May 27, 2008 at 23:17 UTC

close(STDERR)

close(STDIN);
close(STDERR);
open(STDERR, ">/tmp/foo");
print fileno(STDERR), "\n";  # prints 0
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close(STDERR)

STDERR

A quick test of Proc::Daemon indicates that STDIN, STDOUT and STDERR all have the expected file descriptors.

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