OSSL_PROVIDER *OSSL_PROVIDER_load(OPENSSL_CTX *libctx, const char *name);
int OSSL_PROVIDER_unload(OSSL_PROVIDER *prov);
int OSSL_PROVIDER_available(OPENSSL_CTX *libctx, const char *name);
OSSL_PROVIDER *OSSL_PROVIDER_load(OPENSSL_CTX *libctx, const char *name);
int OSSL_PROVIDER_unload(OSSL_PROVIDER *prov);
int OSSL_PROVIDER_available(OPENSSL_CTX *libctx, const char *name);