diff --git a/hnswlib/hnswlib.h b/hnswlib/hnswlib.h
index 58eb7607..61029e90 100644
--- a/hnswlib/hnswlib.h
+++ b/hnswlib/hnswlib.h
@@ -16,20 +16,20 @@
 #include <intrin.h>
 #include <stdexcept>
 #include "cpu_x86.h"
-void cpu_x86::cpuid(int32_t out[4], int32_t eax, int32_t ecx) {
+static void cpu_x86::cpuid(int32_t out[4], int32_t eax, int32_t ecx) {
     __cpuidex(out, eax, ecx);
 }
-__int64 xgetbv(unsigned int x) {
+static __int64 xgetbv(unsigned int x) {
     return _xgetbv(x);
 }
 #else
 #include <x86intrin.h>
 #include <cpuid.h>
 #include <stdint.h>
-void cpuid(int32_t cpuInfo[4], int32_t eax, int32_t ecx) {
+static void cpuid(int32_t cpuInfo[4], int32_t eax, int32_t ecx) {
     __cpuid_count(eax, ecx, cpuInfo[0], cpuInfo[1], cpuInfo[2], cpuInfo[3]);
 }
-uint64_t xgetbv(unsigned int index) {
+static uint64_t xgetbv(unsigned int index) {
     uint32_t eax, edx;
     __asm__ __volatile__("xgetbv" : "=a"(eax), "=d"(edx) : "c"(index));
     return ((uint64_t)edx << 32) | eax;
@@ -51,7 +51,7 @@ uint64_t xgetbv(unsigned int index) {
 // Adapted from https://github.com/Mysticial/FeatureDetector
 #define _XCR_XFEATURE_ENABLED_MASK  0
 
-bool AVXCapable() {
+static bool AVXCapable() {
     int cpuInfo[4];
 
     // CPU support
@@ -78,7 +78,7 @@ bool AVXCapable() {
     return HW_AVX && avxSupported;
 }
 
-bool AVX512Capable() {
+static bool AVX512Capable() {
     if (!AVXCapable()) return false;
 
     int cpuInfo[4];
diff --git a/hnswlib/space_ip.h b/hnswlib/space_ip.h
index b4266f78..d45a4c66 100644
--- a/hnswlib/space_ip.h
+++ b/hnswlib/space_ip.h
@@ -281,10 +281,10 @@ namespace hnswlib {
 #endif
 
 #if defined(USE_SSE) || defined(USE_AVX) || defined(USE_AVX512)
-    DISTFUNC<float> InnerProductSIMD16Ext = InnerProductSIMD16ExtSSE;
-    DISTFUNC<float> InnerProductSIMD4Ext = InnerProductSIMD4ExtSSE;
-    DISTFUNC<float> InnerProductDistanceSIMD16Ext = InnerProductDistanceSIMD16ExtSSE;
-    DISTFUNC<float> InnerProductDistanceSIMD4Ext = InnerProductDistanceSIMD4ExtSSE;
+    static DISTFUNC<float> InnerProductSIMD16Ext = InnerProductSIMD16ExtSSE;
+    static DISTFUNC<float> InnerProductSIMD4Ext = InnerProductSIMD4ExtSSE;
+    static DISTFUNC<float> InnerProductDistanceSIMD16Ext = InnerProductDistanceSIMD16ExtSSE;
+    static DISTFUNC<float> InnerProductDistanceSIMD4Ext = InnerProductDistanceSIMD4ExtSSE;
 
     static float
     InnerProductDistanceSIMD16ExtResiduals(const void *pVect1v, const void *pVect2v, const void *qty_ptr) {
diff --git a/hnswlib/space_l2.h b/hnswlib/space_l2.h
index 44135370..355cc7b8 100644
--- a/hnswlib/space_l2.h
+++ b/hnswlib/space_l2.h
@@ -144,7 +144,7 @@ namespace hnswlib {
 #endif
 
 #if defined(USE_SSE) || defined(USE_AVX) || defined(USE_AVX512)
-    DISTFUNC<float> L2SqrSIMD16Ext = L2SqrSIMD16ExtSSE;
+    static DISTFUNC<float> L2SqrSIMD16Ext = L2SqrSIMD16ExtSSE;
 
     static float
     L2SqrSIMD16ExtResiduals(const void *pVect1v, const void *pVect2v, const void *qty_ptr) {