Re: newbie: Out of order execution in script

[Larry Hall (RFK Partners, Inc)]

At 05:57 PM 11/21/2000, [EMAIL PROTECTED] wrote:


>I'm using the latest 'stable' version of cygwin (1.1.5) on a Win95 platform
>It looks like a script was executed after the statement following the
>script started - out of order execution. Is this possible?
>
>In a script I execute:
>
>importScript=<path>/import.sh
>importMain=<filename>
>tmp=/tmp/$$.gnatmake
>gnatI=${tmp}/gnatI
>outImp=${tmp}/<filename>
>
>${importScript} ${importMain} ${tmp}
>
>sed -e '/(/d'                             \
>     -e 's@/kostabi@@'                     \
>     -e 's@^@\ -aI/kostabi@'               \
>     -e 's@/@\\@g'           ${outImp}.imp > ${gnatI}
>
>The messages below are:
>
>[1] sed: can't read /tmp/398883.gnatmake/device_control_main.imp: No such
>file or directory
>
>[2] Main file:  device_control_main
>
>which come in the exact order shown.
>
>The issue is that message [2] is output by the ${importScript} line, and
>message [1] indicates that the script has not executed.
>
>In looking at ${tmp} I do see a successful generation of the output file
>(${outImp}.imp) indicating that the statement before the 'sed' was run
>successfully. I'm guessing that the 'sed' was executed before the script
>was started, and failed because the output file was not generated. This
>script ran successfully under cywin-b20.1 and I don't see what I'm doing
>wrong.
>
>Any idea what I did?



You used Windows 95 (I wish I were kidding!)  I've noted in the past that
there can be a noticeable lag between when a file is created and when it 
registers in the filesystem.  You can see this lag by running some program
(like touch) which creates a file.  If you watch the directory where the 
file will be created in the Explorer, you will notice there is some lag 
between when you issue the command and when it appears.  This is NOT just
an artifact of the GUI/Explorer but a real delay.  If you ask for the 
existence of the file before it shows up in the Explorer, you will find that
the file is not found.  The solution?  Your best bet is to get a better 
(Windows) O/S.  I haven't checked to see whether this issue persists on 
later 9x versions.  It doesn't happen on NT versions.  Alternatively, you're
left with the option of implementing work-arounds that poll to see if the 
file you know was just created actually exists and to "wait" until it 
actually shows up.  This was the only way I found to guarantee I would get
what I expect.  YMMV.



Larry Hall                              [EMAIL PROTECTED]
RFK Partners, Inc.                      http://www.rfk.com
118 Washington Street                   (508) 893-9779 - RFK Office
Holliston, MA 01746                     (508) 893-9889 - FAX



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