Re: java and status codes.

From:
Nigel Wade <nmw@ion.le.ac.uk>
Newsgroups:
comp.lang.java.programmer
Date:
Thu, 11 Jun 2009 09:57:34 +0100
Message-ID:
<h0qgtu$66b$1@south.jnrs.ja.net>
Donkey Hottie wrote:

horos11 <horos11@gmail.com> wrote in news:237af857-b09d-4881-bafe-
3419ee5c8c34@r33g2000yqn.googlegroups.com:

All,

Much to my dismay, it doesn't look like the exit code with java
(System.exit()) is hooked up with the OS. ie - if I say:

public class samp
{
    public static void main(String[] args)
    {
        System.exit(256);
    }
}

compile and run this as in:

javac samp.java
java samp

and then check the error status from the shell, I get:

echo $? // prints '0'

why is this? Is there a way to get the sun JVM to set $? on failure?
Else, how do you know the program failed, from a shell standpoint?

Ed


I created a shell script

---------------------------
#!/bin/sh

exit 256
---------------------------

It also returns 0

exiting 255 returns 255

So it seems 255 is max return code in (linux). 256 becomes 0.


The UNIX/Linux world uses a 16 bit integer for the return from wait(). The lower
8 bits are the "status" and the upper 8 bits are - I forget. All that gets
passed back to the shell is the lower 8 status bits.

See man 3 exit and man 2 wait, the value returned up the stack by exit(status)
is status&0377.

--
Nigel Wade

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