diff --git a/include/hax.h b/include/hax.h
index 174c8163..a95345f6 100644
--- a/include/hax.h
+++ b/include/hax.h
@@ -218,6 +218,8 @@ void hax_unmap_page(struct hax_page *page);
 void hax_log(int level, const char *fmt, ...);
 void hax_panic(const char *fmt, ...);
 
+uint32_t hax_cpu_id(void);
+
 #ifdef __cplusplus
 }
 #endif
@@ -315,7 +317,6 @@ static inline bool cpu_is_online(hax_cpumap_t *cpu_map, uint32_t cpu_id)
     return !!(((hax_cpumask_t)1 << bit) & map);
 }
 
-extern uint32_t hax_cpu_id(void);
 static inline void get_online_map(void *param)
 {
     hax_cpumap_t *omap = (hax_cpumap_t *)param;
diff --git a/platforms/darwin/hax_wrapper.cpp b/platforms/darwin/hax_wrapper.cpp
index 7f9eece5..fe63a472 100644
--- a/platforms/darwin/hax_wrapper.cpp
+++ b/platforms/darwin/hax_wrapper.cpp
@@ -78,8 +78,8 @@ extern "C" void hax_panic(const char *fmt, ...)
     va_end(args);
 }
 
-extern int cpu_number(void);
-inline uint32_t hax_cpu_id(void)
+extern "C" int cpu_number(void);
+extern "C" uint32_t hax_cpu_id(void)
 {
     return (uint32_t)cpu_number();
 }
diff --git a/platforms/linux/hax_wrapper.c b/platforms/linux/hax_wrapper.c
index ed392da5..e5263a9e 100644
--- a/platforms/linux/hax_wrapper.c
+++ b/platforms/linux/hax_wrapper.c
@@ -81,7 +81,7 @@ void hax_panic(const char *fmt, ...)
     va_end(args);
 }
 
-inline uint32_t hax_cpu_id(void)
+uint32_t hax_cpu_id(void)
 {
     return (uint32_t)smp_processor_id();
 }
diff --git a/platforms/netbsd/hax_wrapper.c b/platforms/netbsd/hax_wrapper.c
index bcd31d3b..78fcc6cc 100644
--- a/platforms/netbsd/hax_wrapper.c
+++ b/platforms/netbsd/hax_wrapper.c
@@ -73,7 +73,7 @@ void hax_panic(const char *fmt,  ...)
     va_end(args);
 }
 
-inline uint32_t hax_cpu_id(void)
+uint32_t hax_cpu_id(void)
 {
     return (uint32_t)cpu_number();
 }
diff --git a/platforms/windows/hax_wrapper.c b/platforms/windows/hax_wrapper.c
index 135c1180..b4dcc92f 100644
--- a/platforms/windows/hax_wrapper.c
+++ b/platforms/windows/hax_wrapper.c
@@ -31,7 +31,7 @@
 #include "hax_win.h"
 #include "../../core/include/ia32.h"
 
-inline uint32_t hax_cpu_id(void)
+uint32_t hax_cpu_id(void)
 {
     PROCESSOR_NUMBER ProcNumber = {0};
     return (uint32_t)KeGetCurrentProcessorNumberEx(&ProcNumber);