+/*
+ * DEFINE_RUN_ONCE_STATIC_ALT: Define an alternative initialiser function. This
+ * function will be declared as static within the file. It takes no arguments
+ * and returns and int result (1 for success or 0 for failure). An alternative
+ * initialiser function is expected to be associated with a primary initialiser
+ * function defined via DEFINE_ONCE_STATIC where both functions use the same
+ * CRYPTO_ONCE object to synchronise. Where an alternative initialiser function
+ * is used only one of the primary or the alternative initialiser function will
+ * ever be called - and that function will be called exactly once. Definitition
+ * of an alternative initialiser function MUST occur AFTER the definition of the
+ * primiary initialiser function.
+ *
+ * Typical usage might be:
+ *
+ * DEFINE_RUN_ONCE_STATIC(myinitfunc)
+ * {
+ * do_some_initialisation();
+ * if (init_is_successful())
+ * return 1;
+ *
+ * return 0;
+ * }
+ *
+ * DEFINE_RUN_ONCE_STATIC_ALT(myaltinitfunc, myinitfunc)
+ * {
+ * do_some_alternative_initialisation();
+ * if (init_is_successful())
+ * return 1;
+ *
+ * return 0;
+ * }
+ */
+#define DEFINE_RUN_ONCE_STATIC_ALT(initalt, init) \
+ static int initalt(void); \
+ static void initalt##_ossl_(void) \
+ { \
+ init##_ossl_ret_ = initalt(); \
+ } \
+ static int initalt(void)
+