[R-SIG-Mac] double dyn.load hang up

[Simon Urbanek]

Roger,

can you give us a simple, reproducible example, please? From your  
description it's not clear to me what is your speculation and what are  
the facts. Running dyn.load twice is very dangerous in general unless  
you know what you're doing, especially with dylibs involving Fortran,  
because those usually contain initializer functions that may have  
unexpected side effects. This is common to all platforms, not just Macs.

Cheers,
Simon


On Aug 25, 2008, at 18:23 , roger koenker wrote:

> I had a rather mysterious problem that now seems to have been
> attributable to dyn.load()ing the same object twice in one R session
> and I would be curious to know if this is a known issue, or something
> that I should try to document further:
>
> I had a single fortran subroutine which I was making into a .so file
> with the usual R CMD SHLIB ritual.  Then I would run a test problem
> which involved dyn.load()ing the .so object, sourcing an R function
> that called .Fortran, generating some random data and finally invoking
> the R function when I sourced a file that looked like this:
>
> # Initial test of parq algorithm
> p <- 30
> n <- 200
> x <- matrix(rnorm(p*n),n,p)
> y <- rnorm(n)
> dyn.load("parq.so")
> source("parq.q")
> z <- parq(x,y,lambda = -1)
>
> That is z contained a perfectly sensible result, but when I sourced  
> this
> file a second time and then tried to look at "z"  the R process  
> hung.  This
> happened on both my old G5 desktop running 2.7.1 and on a new intel
> mac-pancake running 2.7.1.  However, on several other machines 3
> linuxes and one solaris everything was copasetic, no hangups after
> the second invocation.
>
> After much agonizing under the assumption that there was something
> wrong with memory allocation in my fortran -- a hypothesis that had
> quite a lot of historical support -- I finally tried just running  
> the parq
> function without the double  invocation of dyn.load  and this worked
> perfectly.  From which I draw the moral:
>
> 	Don't dyn.load twice, it's not (mac)-nice.
>
> url:    www.econ.uiuc.edu/~roger            Roger Koenker
> email    rkoenker at uiuc.edu            Department of Economics
> vox:     217-333-4558                University of Illinois
> fax:       217-244-6678                Champaign, IL 61820
>
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