diff --git a/src/Distancer.cpp b/src/Distancer.cpp
index 65ba9fd..27f9b51 100644
--- a/src/Distancer.cpp
+++ b/src/Distancer.cpp
@@ -78,7 +78,7 @@ Array<double> * Distancer::run ()
             
             // If no parabolas have been placed, there's nothing else to do
             if (vertices.empty())
-                continue;
+                PARALLEL_LOOP_CONTINUE
             
             // Step back over the data, replacing each element with the value
             // of the lowest parabola at that location
diff --git a/src/Parallel.h b/src/Parallel.h
index 5cf6671..badbe62 100644
--- a/src/Parallel.h
+++ b/src/Parallel.h
@@ -7,21 +7,24 @@
 
 #define PARALLEL_LOOP_START(i,n) \
     dispatch_apply(size_t(n), DISPATCH_APPLY_AUTO, ^(size_t i) {
+#define PARALLEL_LOOP_CONTINUE return;
 #define PARALLEL_LOOP_END });
 
-#elif _OPENMP
+#elif defined(_OPENMP)
 
 #include <omp.h>
 
 #define PARALLEL_LOOP_START(i,n) \
     _Pragma("omp parallel for")  \
     for (size_t i=0; i<size_t(n); i++) {
+#define PARALLEL_LOOP_CONTINUE continue;
 #define PARALLEL_LOOP_END }
 
 #else
 
 #define PARALLEL_LOOP_START(i,n) \
     for (size_t i=0; i<size_t(n); i++) {
+#define PARALLEL_LOOP_CONTINUE continue;
 #define PARALLEL_LOOP_END }
 
 #endif