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| Date: | Wed, 12 Nov 1997 13:38:35 -0800 |
| Content-Type: | text/plain |
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Raymond Roesch writes:
>
> Mark
>
> With sh.hpbin.sys I did the following:
> Server/MANAGER.SYS (7) : run sh.hpbin.sys
>
> $ cd /APACHE/PUB/cgi-bin
> $ sj.pl
> This works correctly.
I think I have this one figured out. When you run sj.pl from the command line
above, it appears to work correctly. But then try the following:
sj.pl >junk.stdout 2>junk.stderr
The junk.stderr file will be empty as expected. But junk.stdout will contain
the showjob output first, followed by all of the HTML, and this will confuse
the web server.
The reason this happens is that by default Perl buffers all output. I
haven't looked at the source to confirm this, but I'm guessing that Perl is
smart enough that if you're printing to a terminal, it will flush the buffers
before calling system() because your system command might also be generating
terminal output. But in the case where you're printing to disk, or to a pipe
as a web server CGI, the pre-system() flush doesn't happen.
The solution to this problem is to tell Perl to not buffer output:
$| = 1;
or
$OUTPUT_AUTOFLUSH = 1;
Add one of those two lines to the beginning of this sample CGI and it will
work correctly.
> #!/bin/perl
> #
> # print your HTTP headers here
> #
>
> print 'Content-type: text/html
>
> <HTML>
> <HEAD>
> <TITLE>Title</TITLE>
> </HEAD>
> <BODY>
> <H1>jobs</H1>
> <PRE>
> ';
> system( "callci sj" );
> print '
> </PRE>
> </BODY>
> </HTML>
> ';
--
Mark Bixby E-mail: [log in to unmask]
Coast Community College Dist. Web: http://www.cccd.edu/~markb/
District Information Services 1370 Adams Ave, Costa Mesa, CA, USA 92626-5429
Technical Support +1 714 438-4647
"You can tune a file system, but you can't tune a fish." - tunefs(1M)
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