f struct ossl_encoder_instance_st OSSL_ENCODER_INSTANCE;
 OSSL_ENCODER *
 OSSL_ENCODER_INSTANCE_get_encoder(OSSL_ENCODER_INSTANCE *encoder_inst);
 void *
 OSSL_ENCODER_INSTANCE_get_encoder_ctx(OSSL_ENCODER_INSTANCE *encoder_inst);
 const char *
 OSSL_ENCODER_INSTANCE_get_output_type(OSSL_ENCODER_INSTANCE *encoder_inst);
 const char *
 OSSL_ENCODER_INSTANCE_get_output_structure(OSSL_ENCODER_INSTANCE *encoder_inst);

 typedef const void *OSSL_ENCODER_CONSTRUCT(OSSL_ENCODER_INSTANCE *encoder_inst,
            