diff --git a/openmp/runtime/src/include/omp.h.var b/openmp/runtime/src/include/omp.h.var
--- a/openmp/runtime/src/include/omp.h.var
+++ b/openmp/runtime/src/include/omp.h.var
@@ -152,6 +152,67 @@
     extern int   __KAI_KMPC_CONVENTION  omp_get_device_num (void);
     typedef void * omp_depend_t;
 
+    /* OpenMP 5.1 interop */
+    typedef intptr_t omp_intptr_t;
+
+    /* 0..omp_get_num_interop_properties()-1 are reserved for implementation-defined properties */
+    typedef enum omp_interop_property {
+        omp_ipr_fr_id = -1,
+        omp_ipr_fr_name = -2,
+        omp_ipr_vendor = -3,
+        omp_ipr_vendor_name = -4,
+        omp_ipr_device_num = -5,
+        omp_ipr_platform = -6,
+        omp_ipr_device = -7,
+        omp_ipr_device_context = -8,
+        omp_ipr_targetsync = -9,
+        omp_ipr_first = -9
+    } omp_interop_property_t;
+
+    #define omp_interop_none 0
+
+    typedef enum omp_interop_rc {
+        omp_irc_no_value = 1,
+        omp_irc_success = 0,
+        omp_irc_empty = -1,
+        omp_irc_out_of_range = -2,
+        omp_irc_type_int = -3,
+        omp_irc_type_ptr = -4,
+        omp_irc_type_str = -5,
+        omp_irc_other = -6
+    } omp_interop_rc_t;
+
+    typedef void * omp_interop_t;
+
+    /*!
+     * The `omp_get_num_interop_properties` routine retrieves the number of implementation-defined properties available for an `omp_interop_t` object.
+     */
+    extern int          __KAI_KMPC_CONVENTION  omp_get_num_interop_properties(const omp_interop_t);
+    /*!
+     * The `omp_get_interop_int` routine retrieves an integer property from an `omp_interop_t` object.
+     */
+    extern omp_intptr_t __KAI_KMPC_CONVENTION  omp_get_interop_int(const omp_interop_t, omp_interop_property_t, int *);
+    /*!
+     * The `omp_get_interop_ptr` routine retrieves a pointer property from an `omp_interop_t` object.
+     */
+    extern void *       __KAI_KMPC_CONVENTION  omp_get_interop_ptr(const omp_interop_t, omp_interop_property_t, int *);
+    /*!
+     * The `omp_get_interop_str` routine retrieves a string property from an `omp_interop_t` object.
+     */
+    extern const char * __KAI_KMPC_CONVENTION  omp_get_interop_str(const omp_interop_t, omp_interop_property_t, int *);
+    /*!
+     * The `omp_get_interop_name` routine retrieves a property name from an `omp_interop_t` object.
+     */
+    extern const char * __KAI_KMPC_CONVENTION  omp_get_interop_name(const omp_interop_t, omp_interop_property_t);
+    /*!
+     * The `omp_get_interop_type_desc` routine retrieves a description of the type of a property associated with an `omp_interop_t` object.
+     */
+    extern const char * __KAI_KMPC_CONVENTION  omp_get_interop_type_desc(const omp_interop_t, omp_interop_property_t);
+    /*!
+     * The `omp_get_interop_rc_desc` routine retrieves a description of the return code associated with an `omp_interop_t` object.
+     */
+    extern const char * __KAI_KMPC_CONVENTION  omp_get_interop_rc_desc(const omp_interop_rc_t, omp_interop_rc_t);
+
     /* kmp API functions */
     extern int    __KAI_KMPC_CONVENTION  kmp_get_stacksize          (void);
     extern void   __KAI_KMPC_CONVENTION  kmp_set_stacksize          (int);