[gambit-list] with-output-to-process hangs in OSX
Marc Feeley
feeley at iro.umontreal.ca
Mon Nov 14 21:04:52 EST 2011
On 2011-11-14, at 8:40 PM, Meng Zhang wrote:
> >> Below are code I wrote to reproduce the problem
> >>
> >> (with-output-to-process
> >> (list path: "sed"
> >> arguments: '("-e" "s/n/N/g"))
> >> (lambda ()
> >> (display "nothing")))
> >>
>
> Actually, I can't get your example to run without an error on v4.6.2 . Can I ask you what you expected your code to do?
> This problem happened in 4.6.1, not 4.6.2
I understand. But you said that once you upgraded to v4.6.2 the problem went away. But when I try with v4.6.2 I get the same result as v4.6.1 on the code above. So I am wondering why there is a difference on v4.6.2.
> It is sending the text "nothing" to sed's input. Are you expecting the output of sed to appear on the terminal?
>
> The procedure with-output-to-process gives to sed a *closed* file descriptor for its stdout. This is why sed complains ("sed: stdout: Broken pipe"). If you didn't want this, you can give an stdout-redirection: #f setting and sed's stdout will be the same as the interpreter's stdout (usually the terminal):
> In 4.6.1, when I run the code above, the current thread sleeps forever.(since the stack frame is at "thread-sleep!")
What happens when you try the code below?
> (with-output-to-process
> (list path: "sed"
> arguments: '("-e" "s/n/N/g")
> stdout-redirection: #f)
> (lambda ()
> (display "nothing\n")))
Do you get the output on the screen?
Marc
More information about the Gambit-list
mailing list