2 files changed, 13 insertions, 4 deletions
diff --git a/test/threads.cxx b/test/threads.cxx
index c7fecffb6..c07b2ea9f 100644
--- a/test/threads.cxx
+++ b/test/threads.cxx
@@ -41,7 +41,7 @@ void magic_number_cb(void *p)
   w->redraw_label();
 }
 
-void* prime_func(void* p)
+extern "C" void* prime_func(void* p)
 {
   Fl_Browser* browser = (Fl_Browser*) p;
   Fl_Value_Output *value;
diff --git a/test/threads.h b/test/threads.h
index c3ebf0c72..73191459b 100644
--- a/test/threads.h
+++ b/test/threads.h
@@ -40,8 +40,11 @@
 #    include <pthread.h>
 
 typedef pthread_t Fl_Thread;
+extern "C" {
+  typedef void *(Fl_Thread_Func)(void *);
+}
 
-static int fl_create_thread(Fl_Thread& t, void *(*f) (void *), void* p) {
+static int fl_create_thread(Fl_Thread& t, Fl_Thread_Func* f, void* p) {
   return pthread_create((pthread_t*)&t, 0, f, p);
 }
 
@@ -51,8 +54,11 @@ static int fl_create_thread(Fl_Thread& t, void *(*f) (void *), void* p) {
 #    include <process.h>
 
 typedef unsigned long Fl_Thread;
+extern "C" {
+  typedef void *(__cdecl Fl_Thread_Func)(void *);
+}
 
-static int fl_create_thread(Fl_Thread& t, void *(*f) (void *), void* p) {
+static int fl_create_thread(Fl_Thread& t, Fl_Thread_Func* f, void* p) {
   return t = (Fl_Thread)_beginthread((void( __cdecl * )( void * ))f, 0, p);
 }
 
@@ -60,8 +66,11 @@ static int fl_create_thread(Fl_Thread& t, void *(*f) (void *), void* p) {
 #    include <process.h>
 
 typedef unsigned long Fl_Thread;
+extern "C" {
+  typedef void *(__cdecl Fl_Thread_Func)(void *);
+}
 
-static int fl_create_thread(Fl_Thread& t, void *(*f) (void *), void* p) {
+static int fl_create_thread(Fl_Thread& t, Fl_Thread_Func* f, void* p) {
   return t = (Fl_Thread)_beginthread((void(* )( void * ))f, 32000, p);
 }
 #  endif // !HAVE_PTHREAD_H