extern ecdsa_t *ecdsa_read_pem_public_key(FILE *fp) __attribute__ ((__malloc__));
extern ecdsa_t *ecdsa_read_pem_private_key(FILE *fp) __attribute__ ((__malloc__));
extern size_t ecdsa_size(ecdsa_t *ecdsa);
-extern bool ecdsa_sign(ecdsa_t *ecdsa, const void *in, size_t inlen, void *out);
-extern bool ecdsa_verify(ecdsa_t *ecdsa, const void *in, size_t inlen, const void *out);
+extern bool ecdsa_sign(ecdsa_t *ecdsa, const void *in, size_t inlen, void *out) __attribute__ ((__warn_unused_result__));
+extern bool ecdsa_verify(ecdsa_t *ecdsa, const void *in, size_t inlen, const void *out) __attribute__ ((__warn_unused_result__));
extern bool ecdsa_active(ecdsa_t *ecdsa);
extern void ecdsa_free(ecdsa_t *ecdsa);