diff --git a/include/mujoco/mjsan.h b/include/mujoco/mjsan.h
index dcacfd9f2c..0afb3bdb2f 100644
--- a/include/mujoco/mjsan.h
+++ b/include/mujoco/mjsan.h
@@ -55,17 +55,17 @@ extern "C" {
 #endif
 
 void mj__markStack(mjData*) __attribute__((noinline));
-static inline void mj_markStack(mjData* d) __attribute__((always_inline)) {
-  asm volatile("" ::: "memory");
+__attribute__((always_inline)) static inline void mj_markStack(mjData* d) {
+  __asm__ volatile("" ::: "memory");
   mj__markStack(d);
-  asm volatile("" ::: "memory");
+  __asm__ volatile("" ::: "memory");
 }
 
 void mj__freeStack(mjData*) __attribute__((noinline));
-static inline void mj_freeStack(mjData* d) __attribute__((always_inline)) {
-  asm volatile("" ::: "memory");
+__attribute__((always_inline)) static inline void mj_freeStack(mjData* d) {
+  __asm__ volatile("" ::: "memory");
   mj__freeStack(d);
-  asm volatile("" ::: "memory");
+  __asm__ volatile("" ::: "memory");
 }
 
 #ifdef __cplusplus