Re: Tk/Tcl

[Paul Gampe <paulg@example.com>]

On Mon, 23 Sep 1996, pal wrote:

pal>Hi All
pal>Sorry for being off the Topic here
pal>
pal>But I'm trying to read and write a Piped Process
pal>within Tcl 
pal>
pal>      set f1 [open {|MYPROG weak.spd} w+]  
pal>I can write
pal>      puts $f1 ls   
pal>
pal>But reading does not seem to work
pal>      gets $f1 var
pal>
pal>any suggestions 

The following segment of code reads correctly from a pipe, so I suspect
that it maybe the use of the 'w+' access mode.  Checking the manual says
that:

r+	Open for reading and writing; the file must exist.
w+	Open for reading and writing. Truncate the file if it already
	exists, otherwise create a new empty file.

So I guess the truncate on a pipe maybe the problem.
Hope that helps,
Paul.

#!/usr/local/bin/tclsh

set f1 [open {|cat /etc/motd} r+]
while {![eof $f1]} {
        gets $f1 var
        puts $var
}
close $f1

pal>leo
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