----- Original Message ----- From: "Sampath Ravindhran" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: 07 December 2004 02:40 Subject: How to terminate STDIN to perl through a mailbox ?
> * Replies will be sent through Spamex to [EMAIL PROTECTED] > * For additional info click -> http://www.spamex.com/i/?v=5111228 > > > 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, since > that could potentially break other non-perl related tasks that might > require to keep the channel open from the parent side. ( I had a similar > situation earlier where the 'perl' binary was invoked in the detached > process without any arguments, and the Perl script itself was fed > through the mailbox as STDIN to the detached process which seemed to > hang forever too. I got over the hang by sending an EOF character as the > last message on the mailbox. Looks like the EOF works for the Perl > script itself on STDIN, but not read of data through STDIN as part of a > Perl script) > > Any suggestions,pointers welcome. Sorry, Ctrl-Z is a terminal driver function. The only way to send EOF is to close the mailbox. The detached process will see EOF when there are no writers to the mailbox. However, you could always modify the perl script to detect Ctrl-Z and process it as if it were EOF: $| = 1; while (<STDIN> && !/\032/ ) { .... } Hope this helps, Ivor.
