[Rd] Telling Windows how to find DLL's from R?
Is it possible to set Windows' search path from within R, or to tell Windows how to find a DLL in some other way from R? Specifically, if a package DLL depends on another DLL the normal requirement is that the second DLL be in the search path so Windows can find it (there are other tricks, but they apply at the Windows level, not at the R level). Thanks, Dominick [[alternative HTML version deleted]] __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] Telling Windows how to find DLL's from R?
On 09/07/2010 2:38 PM, Dominick Samperi wrote: Is it possible to set Windows' search path from within R, or to tell Windows how to find a DLL in some other way from R? Specifically, if a package DLL depends on another DLL the normal requirement is that the second DLL be in the search path so Windows can find it (there are other tricks, but they apply at the Windows level, not at the R level). I haven't tried this, but can't you use Sys.setenv() to change the PATH to what you want? Presumably you'll want to change it back afterwards. Duncan Murdoch __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] Telling Windows how to find DLL's from R?
On 07/09/2010 11:38 AM, Dominick Samperi wrote: > Is it possible to set Windows' search path from within R, or > to tell Windows how to find a DLL in some other way from > R? Specifically, if a package DLL depends on another DLL > the normal requirement is that the second DLL be in the > search path so Windows can find it (there are other tricks, > but they apply at the Windows level, not at the R level). This thread https://stat.ethz.ch/pipermail/r-devel/2008-January/047961.html might be relevant, especially the DLLpath argument to dyn.load. Martin > > Thanks, > Dominick > > [[alternative HTML version deleted]] > > __ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel -- Martin Morgan Computational Biology / Fred Hutchinson Cancer Research Center 1100 Fairview Ave. N. PO Box 19024 Seattle, WA 98109 Location: Arnold Building M1 B861 Phone: (206) 667-2793 __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] Telling Windows how to find DLL's from R?
On Fri, Jul 9, 2010 at 3:48 PM, Duncan Murdoch wrote:
> On 09/07/2010 2:38 PM, Dominick Samperi wrote:
>
>> Is it possible to set Windows' search path from within R, or
>> to tell Windows how to find a DLL in some other way from
>> R? Specifically, if a package DLL depends on another DLL
>> the normal requirement is that the second DLL be in the
>> search path so Windows can find it (there are other tricks,
>> but they apply at the Windows level, not at the R level).
>>
>>
>
>
> I haven't tried this, but can't you use Sys.setenv() to change the PATH to
> what you want? Presumably you'll want to change it back afterwards.
>
Thanks, good suggestion, but it does not seem to work. If PATH is updated in
this way the
change is local to the current process, not to the top-level Windows
process, so a subsequent
dyn.load('foo.dll') will fail if foo.dll depends on bar.dll, unless bar.dll
is placed in the search
path for the top-level shell. Seems like this needs to be done as part of
system
startup outside of R.
On the other hand, if foo.dll is the package library for package foo, and if
foo
depends on package bar, then there is no need to place bar.dll in the
top-level
search path. R takes care of this (more typical) situation.
Dominick
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Re: [Rd] Telling Windows how to find DLL's from R?
Thanks Duncan, Martin: Please ignore my remarks about "top-level Windows context". I made a mistake. After correcting my mistake Duncan's suggestion worked, and the solution is very similar to what the DLLpath argument of dyn.load() does: Sys.setenv() can be used to edit PATH so that Windows finds DLL's where you want them to be found. (Well almost, because the windows search algorithm does not just use PATH.) Dominick [[alternative HTML version deleted]] __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] Telling Windows how to find DLL's from R?
Dominick,
Dominick Samperi wrote:
> On Fri, Jul 9, 2010 at 3:48 PM, Duncan Murdoch
> wrote:
>
>> On 09/07/2010 2:38 PM, Dominick Samperi wrote:
>>
>>> Is it possible to set Windows' search path from within R, or to tell
>>> Windows how to find a DLL in some other way from R? Specifically, if
>>> a package DLL depends on another DLL the normal requirement is that
>>> the second DLL be in the search path so Windows can find it (there
>>> are other tricks, but they apply at the Windows level, not at the R
>>> level).
>>>
>>>
>>
>>
>> I haven't tried this, but can't you use Sys.setenv() to change the
>> PATH to what you want? Presumably you'll want to change it back
>> afterwards.
>>
>
> Thanks, good suggestion, but it does not seem to work. If PATH is
> updated in this way the change is local to the current process, not to
> the top-level Windows process, so a subsequent
> dyn.load('foo.dll') will fail if foo.dll depends on bar.dll, unless
> bar.dll is placed in the search path for the top-level shell. Seems
> like this needs to be done as part of system startup outside of R.
>
> On the other hand, if foo.dll is the package library for package foo,
> and if foo depends on package bar, then there is no need to place
> bar.dll in the top-level search path. R takes care of this (more
> typical) situation.
there is another Windows "feature" which will do the trick for you without
modifying the search path. Windows normally only loads DLLs once, so this
means if you first load the dependent DLL (manually, e.g. using dyn.load())
then the already loaded DLL will be used instead of trying to load one from
path.
E.g. in your example:
dyn.load("mypath/bar.dll")
dyn.load("foo.dll")
will work, as bar.dll (a dependency of foo.dll) is already loaded.
Thomas
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