Clarify what RUN_ONCE returns
RUN_ONCE really just returns 0 on failure or whatever the init
function returned.  By convention, however, the init function must
return 0 on failure and 1 on success.  This needed to be clarified.
* RUN_ONCE - use CRYPTO_THREAD_run_once, and check if the init succeeded
* @once: pointer to static object of type CRYPTO_ONCE
* @init: function name that was previously given to DEFINE_RUN_ONCE,
- * DEFINE_RUN_ONCE_STATIC or DECLARE_RUN_ONCE.
+ * DEFINE_RUN_ONCE_STATIC or DECLARE_RUN_ONCE. This function
+ * must return 1 for success or 0 for failure.
*
- * The return value is 1 on success or 0 in case of error.
+ * The return value is 1 on success (*) or 0 in case of error.
+ *
+ * (*) by convention, since the init function must return 1 on success.
*/
#define RUN_ONCE(once, init) \
(CRYPTO_THREAD_run_once(once, init##_ossl_) ? init##_ossl_ret_ : 0)
