-/* Implement "once" functionality */
-#if !defined(OPENSSL_THREADS)
-typedef int OPENSSL_INIT_ONCE;
-# define OPENSSL_INIT_ONCE_STATIC_INIT 0
-
-static void ossl_init_once_run(OPENSSL_INIT_ONCE *once, void (*init)(void))
-{
- if (*once == OPENSSL_INIT_ONCE_STATIC_INIT) {
- *once = 1;
- init();
- }
-}
-#elif defined(OPENSSL_SYS_WINDOWS)
-# include <windows.h>
-
-# if _WIN32_WINNT < 0x0600
-
-/*
- * Versions before 0x0600 (Windows Vista, Windows Server 2008 or later) do not
- * have InitOnceExecuteOnce, so we fall back to using a spinlock instead.
- */
-typedef LONG OPENSSL_INIT_ONCE;
-# define OPENSSL_INIT_ONCE_STATIC_INIT 0
-
-# define ONCE_UNINITED 0
-# define ONCE_ININIT 1
-# define ONCE_DONE 2
-
-static void ossl_init_once_run(OPENSSL_INIT_ONCE *once, void (*init)(void))
-{
- LONG volatile *lock = (LONG *)once;
- LONG result;
-
- if (*lock == ONCE_DONE)
- return;
-
- do {
- result = InterlockedCompareExchange(lock, ONCE_ININIT, ONCE_UNINITED);
- if (result == ONCE_UNINITED) {
- init();
- *lock = ONCE_DONE;
- return;
- }
- } while (result == ONCE_ININIT);
-}
-
-# else
-
-typedef INIT_ONCE OPENSSL_INIT_ONCE;
-# define OPENSSL_INIT_ONCE_STATIC_INIT INIT_ONCE_STATIC_INIT
-
-static BOOL CALLBACK once_cb(PINIT_ONCE once, PVOID initfp, PVOID *unused)
-{
- void (*init)(void) = initfp;
-
- init();
-
- return TRUE;
-}
-
-static void ossl_init_once_run(OPENSSL_INIT_ONCE *once, void (*init)(void))
-{
- InitOnceExecuteOnce((INIT_ONCE *)once, once_cb, init, NULL);
-}
-# endif
-#else /* pthreads */
-# include <pthread.h>
-
-typedef pthread_once_t OPENSSL_INIT_ONCE;
-# define OPENSSL_INIT_ONCE_STATIC_INIT PTHREAD_ONCE_INIT
-
-static void ossl_init_once_run(OPENSSL_INIT_ONCE *once, void (*init)(void))
-{
- pthread_once(once, init);
-}
-#endif
-