Craig,
Thanks for your suggestion. The parent process is indeed in C. But,
because the C code executing in the parent is common to both the
situations I describe below, namely, the case where perl expects to
read a script itself through stdin, and the case where perl runs a
script which in turn expects to read data through stdin, I had to go
with a common solution. I therefore went with the suggestion given by
Ivor of simply checking for the value 26 in the stdin and exiting the
loop. ( It's possible that your suggestion of decc$write_eof_to
mailbox() might also work in both cases, but since I had a working
solution.
Thanks,
Sam
Craig Berry wrote:
On Monday, December 06, 2004, at 08:40PM, Sampath Ravindhran <[EMAIL PROTECTED]> wrote:
I have an application that spawns a detached process to run a Perl
script, within which it expects to read a bunch of lines from STDIN. To
do this, I have a simple construct like
-----------
while (<STDIN>)
{
$myline = $_;
(process my input line...)
}
------------
Before calling the perl script in the detached process, I define
sys$input to the mailbox device the parent had created.
When the parent process writes text lines into the mailbox, I find that
the detached process *does* receive them. After writing the necessary
lines, I send an EOF character (decimal 26) to the mailbox expecting it
to terminate read from STDIN and proceed further with the execution of
the Perl script. However, that doesn't happen and the Perl execution
remains in this while loop forever. Closing the channel of the mailbox
after the write operation is not a desirable option at this point
It sounds like what you need is the equivalent of decc$write_eof_to mailbox. See
http://h71000.www7.hp.com/doc/732FINAL/5763/5763pro_027.html#decc_write_eof_mbx__sec
Since I don't know how that's implemented, I don't know if you could just wrap some XS around it and make it callable from Perl. But it's also not clear to me in your example if the parent process is in Perl or something else. If it's in C, give the above a try and see if it works. I suspect it's just doing a special $QIO to the mailbox channel in a way that bypasses interpretation of the EOF character by the CRTL writes. If the parent is in Perl, you could also try calling VMS::Stdio::binmode on the filehandle before sending the EOF character. I really have no idea whether that will work, but it's something to try.
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