Message-ID: <E66794E69CFDE04D9A70842786030B931C308F30@PA-MBX01.na.tibco.com>
Date: 2013-07-02T16:16:52Z
From: William Dunlap
Subject: Ctrl+C in R will terminate the child process which is spawned by using "pipe"
In-Reply-To: <OF918D6FB5.0BE55AA5-ON48257B9C.005569B6-48257B9C.0056AE15@cn.ibm.com>
If you are on a Unix-like machine try using the setsid command to
run your command in a 'session' of its own. E.g.,
> z <- pipe("setsid /usr/bin/yes", open="r")
> length(readLines(z, n=1e6))
[1] 1000000
> # hit control-C
> length(readLines(z, n=1e6))
[1] 1000000
> length(readLines(z, n=1e6))
[1] 1000000
> close(z)
as opposed to
> z <- pipe("/usr/bin/yes", open="r")
> length(readLines(z, n=1e6))
[1] 1000000
> # hit control-C
> length(readLines(z, n=1e6)) # this reads what is left in the stdin buffer
[1] 34240
> length(readLines(z, n=1e6))
[1] 0
> close(z)
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com
> -----Original Message-----
> From: r-devel-bounces at r-project.org [mailto:r-devel-bounces at r-project.org] On Behalf
> Of Rong lI Li
> Sent: Tuesday, July 02, 2013 8:46 AM
> To: r-devel at r-project.org
> Subject: [Rd] Ctrl+C in R will terminate the child process which is spawned by using "pipe"
>
>
> Hi, all,
>
> I pressed Ctrl+C in R process, and found that the child process which was
> spawned by using "pipe" is terminated due to this.
> Are there any way to work around it, so that the child process can run
> happily without being terminated? Or can we block the signal for the child
> process?
>
> 1. I used pipe to spawn one C++ process, which will running in a loop
> without exiting immediately.
>
> z <- pipe("./mytest", open = "r+")
> > z
> description class mode text opened can read
> "./mytest" "pipe" "r+" "text" "opened" "yes"
> can write
> "no"
>
> 2. When I press "Ctrl+C" in the current R shell, I found the forked child
> process was also terminated. Are there any way to work around it?
>
> =====================
>
> Rong "Jessica", Li (????)
> Platform Symphony TET, CSTL, IBM Systems &Technology Group, Development
> Tel:86-10-82451010 Email:ronglli at cn.ibm.com
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