[R-SIG-Mac] Forking issues in Mavericks

Jeroen Ooms jeroen.ooms at stat.ucla.edu
Tue Oct 29 20:53:38 CET 2013

On Tue, Oct 29, 2013 at 12:35 PM, Steve Lianoglou
<lianoglou.steve at gene.com> wrote:
> Is this happening when you are running R from w/in R.app (which, I
> think, is not new), or are you running R from the terminal and still
> seeing this)?

It happens when a forked child process tries to use some "fork unsafe"
opratation, after the parent has already done so as well, see [1]. It
is related to R.app in the sense that the GUI uses the CF event
loop which is considered fork unsafe, and therefore a forked child
process can't do any fork unsafe operations anymore. However it also
happens in other contexts such as prefork in RApache [2].

But my actual question is: what is it about using httr::GET that is
considered fork "unsafe", which was not considered unsafe in 10.8?

[1] http://objectivistc.tumblr.com/post/16187948939/you-must-exec-a-core-foundation-fork-safety-tale
[2] http://stackoverflow.com/questions/2344368/problem-configuring-rapache-on-os-x-10-5-8/2358834#2358834

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