Le 09/06/10 03:04, Davor Cubranic a écrit :
Hi there,
I have a question about the murky world of R internals, DLLs, and their
interaction with Rcpp.
There are some C routines in the 'stats' package that I would like to call
directly from my Rcpp-based package, e.g., loess_raw. However, 'stats' only
exposes them to R callers, not C or C++. (I.e., it does not use
R_RegisterCCallable, but they are among R_CMethodDef's passed in
R_registerRoutines.)
Reading the information on writing R extensions, it sounds like there may not
be a way to get to the address of an object in another package's DLL. (In this
case, in stats.so.) However, there is a NativeSymbolInfo for
stats:::R_loess_raw, which includes all sorts of info about the C method. Is
there a way that this can be used to get a function pointer to it from within
my code? And if this is too unportable, is there a cleaner way?
Thanks,
Davor
Hi,
I see
> getNativeSymbolInfo( "loess_raw" )
$name
[1] "loess_raw"
$address
<pointer: 0x103092820>
attr(,"class")
[1] "NativeSymbol"
$package
DLL name: stats
Filename:
/Library/Frameworks/R.framework/Resources/library/stats/libs/x86_64/stats.so
Dynamic lookup: FALSE
$numParameters
[1] 24
attr(,"class")
[1] "CRoutine" "NativeSymbolInfo"
So I'd probably look into the implementation of getNativeSymbolInfo
(R_getSymbol in file Rdynload.c) and figure out what sort of pointer is
the $address here. once you know that I suppose you can use it.
There is a good chance the pointer is a DL_FUNC. You probably want to
look at the Rdynpriv.h file too.
Maybe this question is more suited to R-devel.
Romain
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Romain Francois
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