diff --git a/SuperBuild/SuperBuild.cmake b/SuperBuild/SuperBuild.cmake
index 718d45e..dc6b2ef 100644
--- a/SuperBuild/SuperBuild.cmake
+++ b/SuperBuild/SuperBuild.cmake
@@ -21,13 +21,13 @@ endif()
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
 
 option(USE_STATIC_RUNTIME "Use static runtime" ON)
+option(OPENMP_XCODE "Build the static library" OFF)
 
 include(ExternalProject)
 
 set(DEPENDENCIES)
 
 set(DEP_INSTALL_DIR ${CMAKE_BINARY_DIR})
-
 set(ZLIB_IMPLEMENTATION "Cloudflare" CACHE STRING "Choose zlib implementation.")
 set_property(CACHE ZLIB_IMPLEMENTATION PROPERTY STRINGS  "Cloudflare;System;Custom")
 if(${ZLIB_IMPLEMENTATION} STREQUAL "Cloudflare")
@@ -55,6 +55,7 @@ ExternalProject_Add(src
         -DCMAKE_INSTALL_PREFIX:PATH=${CMAKE_BINARY_DIR}
         -DCMAKE_C_FLAGS:STRING=${CMAKE_C_FLAGS}
         -DCMAKE_VERBOSE_MAKEFILE:BOOL=${CMAKE_VERBOSE_MAKEFILE}
+        -DOPENMP_XCODE:BOOL=${OPENMP_XCODE}
         -DUSE_STATIC_RUNTIME:BOOL=${USE_STATIC_RUNTIME}
         -DZLIB_IMPLEMENTATION:STRING=${ZLIB_IMPLEMENTATION}
         -DZLIB_ROOT:PATH=${ZLIB_ROOT}
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 19d9bd3..ff07b0a 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -18,11 +18,16 @@ if(NOT CMAKE_BUILD_TYPE)
     set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS  "Debug;Release;RelWithDebInfo;MinSizeRel")
 endif()
 
-
+#e.g.  cmake -DOPENMP_XCODE=ON ..
+option(OPENMP_XCODE "Build the static library" OFF)
 if(${CMAKE_C_COMPILER_ID} STREQUAL "AppleClang")
     # using AppleClang
     add_definitions(-fno-caret-diagnostics)
-    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,-dead_strip")
+    if (OPENMP_XCODE)
+        set(CMAKE_C_FLAGS "-I/usr/local/include -Xclang -fopenmp ${CMAKE_C_FLAGS} ${OpenMP_C_FLAGS}")
+        set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -L/usr/local/lib -lomp")
+    endif()
+	set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,-dead_strip")
 elseif(${CMAKE_C_COMPILER_ID} STREQUAL "GNU")
     # using GCC
     set(CMAKE_C_STANDARD 11)
diff --git a/src/core32.c b/src/core32.c
index 4281ce5..9bc235b 100644
--- a/src/core32.c
+++ b/src/core32.c
@@ -589,7 +589,6 @@ static int nifti_smooth_gauss(nifti_image * nim, flt SigmammX, flt SigmammY, flt
 	for (int i = 2; i < 8; i++ )
 		nRow *= MAX(nim->dim[i],1);
 	#if defined(_OPENMP)
-	//printf(">>>%d\n", omp_get_num_threads());
 	if (omp_get_max_threads() > 1)
 		blurP(img, nim->nx, nRow, nim->dx, SigmammX);
 	else
@@ -636,10 +635,9 @@ static int nifti_smooth_gauss(nifti_image * nim, flt SigmammX, flt SigmammY, flt
 	//BLUR Z:
 	if ((SigmammZ <= 0.0) || (nim->nz < 2)) return 0; //all done!
 	nRow = nim->nx * nim->ny; //transpose XYZ to ZXY and blur Z columns with XY Rows
-	//#pragma omp parallel
-	//#pragma omp for
 	#pragma omp parallel for
 	for (int v = 0; v < nVol; v++ ) { //transpose each volume separately
+	    //printf("volume %d uses thread %d\n", v, omp_get_thread_num()); 
 		flt * img3D = (flt *)_mm_malloc(nvox3D*sizeof(flt), 64); //alloc for each volume to allow openmp
 		size_t vo = v * nvox3D; //volume offset
 		for (int z = 0; z < nz; z++ ) {