diff --git a/.gitignore b/.gitignore
index f1f9400ab..4551c79cc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,7 +2,7 @@
 *.slo
 *.lo
 *.o
-
+*.page
 # Compiled Dynamic libraries
 *.so
 *.dylib
diff --git a/R-package/src/Makevars b/R-package/src/Makevars
index 7dfda4d57..b0d3283b9 100644
--- a/R-package/src/Makevars
+++ b/R-package/src/Makevars
@@ -5,9 +5,10 @@ CXX=`R CMD config CXX`
 CFLAGS=`R CMD config CFLAGS` 
 # expose these flags to R CMD SHLIB
 PKG_CPPFLAGS= -DXGBOOST_CUSTOMIZE_ERROR_ -I$(PKGROOT)  $(SHLIB_OPENMP_CFLAGS)
-XGBFLAG= $(CFLAGS) -DXGBOOST_CUSTOMIZE_ERROR_ -fPIC  $(SHLIB_OPENMP_CFLAGS)
+PKG_CPPFLAGS+= $(SHLIB_PTHREAD_FLAGS)
+XGBFLAG= $(CFLAGS) -DXGBOOST_CUSTOMIZE_ERROR_ -fPIC  $(SHLIB_OPENMP_CFLAGS) $(SHLIB_PTHREAD_FLAGS)
 
-PKG_LIBS = $(SHLIB_OPENMP_CFLAGS)
+PKG_LIBS = $(SHLIB_OPENMP_CFLAGS) $(SHLIB_PTHREAD_FLAGS)
 
 ifeq ($(no_omp),1)
 	PKG_CPPFLAGS += -DDISABLE_OPENMP 
diff --git a/R-package/src/Makevars.win b/R-package/src/Makevars.win
index 3df9891fc..8f5f7ed98 100644
--- a/R-package/src/Makevars.win
+++ b/R-package/src/Makevars.win
@@ -5,8 +5,9 @@ CXX=`Rcmd config CXX`
 CFLAGS=`Rcmd config CFLAGS` 
 # expose these flags to R CMD SHLIB
 PKG_CPPFLAGS= -DXGBOOST_CUSTOMIZE_ERROR_ -I$(PKGROOT)  $(SHLIB_OPENMP_CFLAGS)
-XGBFLAG= $(CFLAGS) -DXGBOOST_CUSTOMIZE_ERROR_ -fPIC  $(SHLIB_OPENMP_CFLAGS)
-PKG_LIBS = $(SHLIB_OPENMP_CFLAGS)
+PKG_CPPFLAGS+= $(SHLIB_PTHREAD_FLAGS)
+XGBFLAG= $(CFLAGS) -DXGBOOST_CUSTOMIZE_ERROR_ -fPIC  $(SHLIB_OPENMP_CFLAGS) $(SHLIB_PTHREAD_FLAGS)
+PKG_LIBS = $(SHLIB_OPENMP_CFLAGS) $(SHLIB_PTHREAD_FLAGS)
 
 ifeq ($(no_omp),1)
 	PKG_CPPFLAGS += -DDISABLE_OPENMP 
diff --git a/src/io/page_dmatrix-inl.hpp b/src/io/page_dmatrix-inl.hpp
index e16beb4b6..8db944c85 100644
--- a/src/io/page_dmatrix-inl.hpp
+++ b/src/io/page_dmatrix-inl.hpp
@@ -50,13 +50,13 @@ struct RowBatchPage {
     std::vector<size_t> &rptr = *p_rptr;
     rptr.resize(this->Size() + 1);
     for (size_t i = 0; i < rptr.size(); ++i) {
-      rptr[i] = static_cast<size_t>(this->row_ptr(i));
+      rptr[i] = static_cast<size_t>(this->row_ptr(static_cast<int>(i)));
     }
     batch.ind_ptr = &rptr[0];
     return batch;
   }
   /*! \brief get i-th row from the batch */
-  inline RowBatch::Inst operator[](size_t i) {
+  inline RowBatch::Inst operator[](int i) {
     return RowBatch::Inst(data_ptr(0) + row_ptr(i), 
                           static_cast<bst_uint>(row_ptr(i+1) - row_ptr(i)));
   }
@@ -173,7 +173,7 @@ class ThreadRowPageIterator: public utils::IIterator<RowBatch> {
   // loader factory for page
   struct Factory {
    public:
-    size_t file_begin_;
+    long file_begin_;
     utils::FileStream fi;
     Factory(void) {}
     inline void SetFile(const utils::FileStream &fi) {
diff --git a/src/utils/io.h b/src/utils/io.h
index dbfcee3f6..276dd7312 100644
--- a/src/utils/io.h
+++ b/src/utils/io.h
@@ -92,9 +92,9 @@ class IStream {
 class ISeekStream: public IStream {
  public:
   /*! \brief seek to certain position of the file */
-  virtual void Seek(size_t pos) = 0;
+  virtual void Seek(long pos) = 0;
   /*! \brief tell the position of the stream */
-  virtual size_t Tell(void) = 0;
+  virtual long Tell(void) = 0;
 };
 
 /*! \brief implementation of file i/o stream */
@@ -112,11 +112,11 @@ class FileStream : public ISeekStream {
   virtual void Write(const void *ptr, size_t size) {
     fwrite(ptr, size, 1, fp);
   }
-  virtual void Seek(size_t pos) {
+  virtual void Seek(long pos) {
     fseek(fp, pos, SEEK_SET);
   }
-  virtual size_t Tell(void) {
-    return static_cast<size_t>(ftell(fp));
+  virtual long Tell(void) {
+    return ftell(fp);
   }
   inline void Close(void) {
     if (fp != NULL){
diff --git a/wrapper/xgboost.py b/wrapper/xgboost.py
index adf59c829..e4338e0cd 100644
--- a/wrapper/xgboost.py
+++ b/wrapper/xgboost.py
@@ -56,7 +56,7 @@ class DMatrix:
                         weight for each instances                        
         """
         # force into void_p, mac need to pass things in as void_p
-        if data == None:
+        if data is None:
             self.handle = None
             return
         if isinstance(data, str):
@@ -484,7 +484,7 @@ def train(params, dtrain, num_boost_round = 10, evals = [], obj=None, feval=None
             feval:
     """
     bst = Booster(params, [dtrain]+[ d[0] for d in evals ] )
-    if obj == None:
+    if obj is None:
         for i in range(num_boost_round):
             bst.update( dtrain, i )
             if len(evals) != 0: