[R-SIG-Mac]Compiling R libraries on MAC OS X

[Stephen Eglen]

Jan de Leeuw writes:
 > If you use flat namespaces you cannot have multiple definitions of  
 > symbols,
 > because the linked application has no way of knowing which definition
 > you meant. There are a number of ways to deal with this. You can use
 > two-level namespaces (which give warnings for multiple definitions)
 > 
 > > gcc -bundle -bundle-loader /usr/local/lib/R/bin/R.bin -undefined error  
 > > -L/sw/lib -L/usr/local/lib -o sjevor.so edgelist.o geometry.o heap.o  
 > > main.o memory.o output.o sjevor.o voronoi.o
 > 
 > You can change the C code such that all definitions but one use extern  
 > (this is best). And you can force the link by adding the
 > -m flag, which also transforms errors to warnings, i.e.
 > 
 > > gcc -bundle -flat_namespace -undefined suppress -Xlinker -m -L/sw/lib  
 > > -L/usr/local/lib -o sjevor.so edgelist.o geometry.o heap.o main.o  
 > > memory.o output.o sjevor.o voronoi.o

Thanks very much Jan for your help.  I have updated the C code so that
the global variables are defined once, and then "extern"ed in other
files that need them.  This works very well.

Stephen