Question

I've built an R package which includes C/C++ code. I am now trying to test this package on win-builder. Unfortunately, the following error is returned in 00install.out:

* installing *source* package 'mypackage' ...
** libs
  running 'src/Makefile.win' ...
/usr/bin/make --directory=lib/mylib/
gcc -g -Wall -fPIC -c mycode.c
make[1]: gcc: Command not found
make[1]: *** [mycode.o] Error 127
make: *** [mylib] Error 2
Warning: running command 'make --no-print-directory -f "Makefile.win"' had status 2
ERROR: compilation failed for package 'mypackage'
* removing 'd:/RCompile/CRANguest/R-release/lib/mypackage'

Trying with gcc, gcc.exe, and cc yielded similar results.

Accordingly, I set up a testing environment on a Windows virtual machine according to these instructions. Running R CMD INSTALL . on the code from the command line within this environment resulted in the code compiling and the package installing without issue. (Running R CMD build . also yielded no errors.)

What's up with win-builder, and how can I achieve compilation on it?

Or, more importantly, is being able to build the package on Windows sufficient, regardless of whether it worked on win-builder?

My Makefile.win is as follows:

export CCOMP = gcc
export CPPCOMP = c++
export ADD_CC_FLAGS = -O3
APP_DIR = ./apps/myapp
LIB_DIR = ./lib/mylib

.PHONY: all $(APP_DIR) $(LIB_DIR)

all: $(APP_DIR) $(LIB_DIR)

$(APP_DIR) $(LIB_DIR): mylib
  $(MAKE) --directory=$@

$(APP_DIR): $(LIB_DIR) mylib

mylib:
  $(MAKE) --directory=lib/mylib

Inserting echo %PATH% into the make file under the mylib target yielded:

Makefile.win:24: *** missing separator.  Stop.

Answer 1

You get an obscure error here because you included a file Makefile.win.

But the semantics of make, if such a file is found, it will be used ... which is not what you want here. R builds its own Makefile.win and you are supposed to only supply a snippet to be included -- which must be called Makevars.win.

That is rule number one. Rules number two is to not included all the material you would include in a Makefile -- as you would clobber what R already brings to the table. All this is in Writing R Extensions but could of course be clearer.

My pragmatic suggestion: take a package you know and like which has a working R build in win-builder, and modify it. You can test locally should you have access to an R system with Rtools etc pp.

Edit from OP:

I needed to compile an executable which relied on several libraries. The library codes were in src/libs and the executable's code was in src/apps. I ensured that running make within each subdirectory worked and set src/apps/Makefile to use relative paths to pull in the results of src/libs. The only problem then, was getting the whole chain running. To do so, I created a file src/Makevars.win which had the following structure:

.PHONY: all myprogram sublib1 sublib2

all: sublib1 sublib2 myprogram

myprogram: sublib1 sublib2
  @(cd apps/myprogram && $(MAKE) CXX="$(CXX)" CC="$(CC)" CFLAGS="$(CFLAGS) $(CPICFLAGS)" AR="$(AR)" RANLIB="$(RANLIB)")

sublib1:
  @(cd lib/sublib1    && $(MAKE) CXX="$(CXX)" CC="$(CC)" CFLAGS="$(CFLAGS) $(CPICFLAGS)" AR="$(AR)" RANLIB="$(RANLIB)")

sublib2:
  @(cd lib/sublib2    && $(MAKE) CXX="$(CXX)" CC="$(CC)" CFLAGS="$(CFLAGS) $(CPICFLAGS)" AR="$(AR)" RANLIB="$(RANLIB)")

As I understand it, Makevars.win gets embedded in a dynamically generated Makefile that R produces. So, $(CC) is actually referencing this hidden code.

(There are probably more clever ways to do this.)

gcc not found by win-builder

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