I released inline 0.3.6 yesterday. This is a minor release which gives better R level errors when there is a compiler error. For example : 

> tryCatch( cxxfunction( , 'int x = 3 ; x+ ; return R_NilValue ; ' ), error = function(e) print(e$message))
file10d63af1.cpp: In function ‘SEXPREC* file10d63af1()’:
file10d63af1.cpp:18: error: expected primary-expression before ‘;’ token
make: *** [file10d63af1.o] Error 1

ERROR(s) during compilation: source code errors or compiler configuration errors!

Program source:
  1: // includes from the plugin
  2: #include <R.h>
  3: #include <Rdefines.h>
  4: #include <R_ext/Error.h>
  5: 
  6: 
  7: // user includes
  8: 
  9: 
 10: // declaration
 11: extern "C" {
 12: SEXP file10d63af1( ) ;
 13: }
 14: 
 15: // definition
 16: 
 17: SEXP file10d63af1(  ){
 18: int x = 3 ; x+ ; return R_NilValue ;  
 19: Rf_warning("your C++ program does not return anything"); 
 20:  return R_NilValue ; 
 21: }
 22: 
 23: 
[1] "Compilation ERROR, function(s)/method(s) not created! file10d63af1.cpp: In function ‘SEXPREC* file10d63af1()’:\nfile10d63af1.cpp:18: error: expected primary-expression before ‘;’ token\nmake: *** [file10d63af1.o] Error 1"

The compile error is part of the message of the R error, with previous versions, the R error always had the same message "Compilation ERROR, function(s)/method(s) not created!".

This will be especially useful for developing Rcpp, which rely on inline for unit testing