Index: asmrun/startup.c
===================================================================
--- asmrun/startup.c	(Revision 13246)
+++ asmrun/startup.c	(Arbeitskopie)
@@ -147,6 +147,14 @@
 extern void caml_init_ieee_floats (void);
 extern void caml_init_signals (void);
 
+#ifdef _MSC_VER
+
+/* PR 4887: avoid crash box of windows runtime on some system calls */
+extern void caml_install_invalid_parameter_handler();
+
+#endif
+
+
 void caml_main(char **argv)
 {
   char * exe_name;
@@ -157,6 +165,9 @@
   char tos;
 
   caml_init_ieee_floats();
+#ifdef _MSC_VER
+  caml_install_invalid_parameter_handler();
+#endif
   caml_init_custom_operations();
 #ifdef DEBUG
   caml_verb_gc = 63;
Index: byterun/win32.c
===================================================================
--- byterun/win32.c	(Revision 13246)
+++ byterun/win32.c	(Arbeitskopie)
@@ -477,3 +477,23 @@
   data[2] = GetCurrentProcessId();
   return 3;
 }
+
+
+#ifdef _MSC_VER
+
+static void invalid_parameter_handler(const wchar_t* expression,
+   const wchar_t* function,
+   const wchar_t* file,
+   unsigned int line,
+   uintptr_t pReserved)
+{
+  /* no crash box */
+}
+
+
+void caml_install_invalid_parameter_handler()
+{
+  _set_invalid_parameter_handler(invalid_parameter_handler);
+}
+
+#endif 
Index: byterun/startup.c
===================================================================
--- byterun/startup.c	(Revision 13246)
+++ byterun/startup.c	(Arbeitskopie)
@@ -332,6 +332,13 @@
 extern void caml_signal_thread(void * lpParam);
 #endif
 
+#ifdef _MSC_VER
+ 
+/* PR 4887: avoid crash box of windows runtime on some system calls */
+extern void caml_install_invalid_parameter_handler();
+
+#endif
+
 /* Main entry point when loading code from a file */
 
 CAMLexport void caml_main(char **argv)
@@ -349,6 +356,9 @@
   /* Machine-dependent initialization of the floating-point hardware
      so that it behaves as much as possible as specified in IEEE */
   caml_init_ieee_floats();
+#ifdef _MSC_VER
+  caml_install_invalid_parameter_handler();
+#endif
   caml_init_custom_operations();
   caml_ext_table_init(&caml_shared_libs_path, 8);
   caml_external_raise = NULL;