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R CMD check: Error in .C

5 messages · Etienne Laliberté, Duncan Murdoch, Mathieu Ribatet +1 more

Original
Etienne Laliberté
# 
Function/file names are hypothetical. Say I have written myfunction.R,
which calls myfunction.c via .C("myfunction", ...).

I've compiled successfully myfunction.c via R CMD SHLIB myfunction.c
in the terminal. Then, in the R console:

dyn.load("myfunction.so")
source("myfunction.R")
test <- myfunction() # works fine

So everything is in order, myfunction works perfectly.

Now I want to include myfunction() into a package called mypackage.
Here's what I did:

1) I've added PACKAGE = "mypackage" in the .C() line in myfunction.R.
2) I put myfunction.R into the R folder of mypackage
3) I put myfunction.c into the src folder of mypackage
4) I created myfunction.Rd into the man folder

I then build the package via R CMD build mypackage. All good. However,
when I run R CMD check mypackage, I get the following error (note that
I translated from french, might be a bit different in english):

Error in .C("myfunction", ...): C symbol name "myfunction" cannot be
found in the DLL for package "mypackage"

I would appreciate some help here. Please do not refer my to "Writing
R extensions" - if the answer's in there, I don't understand it.

Many thanks.

--
Etienne Lalibert?
================================
Rural Ecology Research Group
School of Forestry
University of Canterbury
Private Bag 4800
Christchurch 8140, New Zealand
Phone: +64 3 366 7001 ext. 8365
Fax: +64 3 364 2124
www.elaliberte.info
Duncan Murdoch
#
Etienne Lalibert? wrote:
What do you get from R CMD INSTALL mypackage? 

Duncan Murdoch
Mathieu Ribatet
# 
Dear Etienne,

You probably want to create a zzz.R file in the /mypkg/R/ folder which
is just

        .First.lib <- function(lib, pkg){
          library.dynam("MyPkgName", package = pkg, lib.loc = lib)
          return(invisible(0))
        }

This would ensure that your shared library will be loaded.

Best,
Mathieu
        
Le lundi 26 octobre 2009 ? 03:58 +0100, Etienne Lalibert? a ?crit :
Etienne Laliberté
# 
Many thanks Mathieu, following your answer I did a bit more focused
research and found out that because "mypackage" had a NAMESPACE, I had
to create the following zzz.R file instead:

.onLoad <-function (lib, pkg) {
    library.dynam("mypackage", pkg, lib)
}

I then had a look in "Writing R extensions" to see if I had just
missed this precious info, but though they mention:

    "If the ?src? subdirectory of an add-on package contains source
code with one of the extensions
listed above or a file ?Makevars? but not a file Makefile, R CMD
INSTALL creates a shared object
(for loading into R in the .First.lib or .onLoad function of the
package) using the R CMD
SHLIB mechanism. If file ?Makevars? exists it is read first, then the
system makefile and then
any personal ?Makevars? files."

To a novice like me, I really think this is not clear enough. It would
be nice if "Writing R extensions" was a bit more explicit about this
zzz.R solution.


Le 26 octobre 2009 23:44, Mathieu Ribatet <mathieu.ribatet at epfl.ch> a ?crit :
--
Etienne Lalibert?
================================
Rural Ecology Research Group
School of Forestry
University of Canterbury
Private Bag 4800
Christchurch 8140, New Zealand
Phone: +64 3 366 7001 ext. 8365
Fax: +64 3 364 2124
www.elaliberte.info
Friedrich Leisch
# 
[ Note that this discussion really belongs to r-help, not r-devel, but
a nyway.
> Many thanks Mathieu, following your answer I did a bit more focused
  > research and found out that because "mypackage" had a NAMESPACE, I had
  > to create the following zzz.R file instead:

  > .onLoad <-function (lib, pkg) {
  >     library.dynam("mypackage", pkg, lib)
  > }

If you have a namespace you only need a

  useDynLib(mypackage)

in the NAMESPACE file, everything else is done automatically for you
(no need for the above zzz.R).

Best,
Fritz