diff --git a/src/libsodium/include/sodium/core.h b/src/libsodium/include/sodium/core.h
index 7faa983e..3ca44762 100644
--- a/src/libsodium/include/sodium/core.h
+++ b/src/libsodium/include/sodium/core.h
@@ -9,7 +9,8 @@ extern "C" {
 #endif
 
 SODIUM_EXPORT
-int sodium_init(void);
+int sodium_init(void)
+            __attribute__ ((warn_unused_result));
 
 #ifdef __cplusplus
 }
diff --git a/src/libsodium/include/sodium/crypto_aead_aes256gcm.h b/src/libsodium/include/sodium/crypto_aead_aes256gcm.h
index 9b9f7ed3..42c0c830 100644
--- a/src/libsodium/include/sodium/crypto_aead_aes256gcm.h
+++ b/src/libsodium/include/sodium/crypto_aead_aes256gcm.h
@@ -54,7 +54,8 @@ int crypto_aead_aes256gcm_decrypt(unsigned char *m,
                                   const unsigned char *ad,
                                   unsigned long long adlen,
                                   const unsigned char *npub,
-                                  const unsigned char *k);
+                                  const unsigned char *k)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 int crypto_aead_aes256gcm_beforenm(crypto_aead_aes256gcm_state *ctx_,
@@ -80,7 +81,9 @@ int crypto_aead_aes256gcm_decrypt_afternm(unsigned char *m,
                                           const unsigned char *ad,
                                           unsigned long long adlen,
                                           const unsigned char *npub,
-                                          const crypto_aead_aes256gcm_state *ctx_);
+                                          const crypto_aead_aes256gcm_state *ctx_)
+            __attribute__ ((warn_unused_result));
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/libsodium/include/sodium/crypto_aead_chacha20poly1305.h b/src/libsodium/include/sodium/crypto_aead_chacha20poly1305.h
index 49e6bd40..1c0b85ba 100644
--- a/src/libsodium/include/sodium/crypto_aead_chacha20poly1305.h
+++ b/src/libsodium/include/sodium/crypto_aead_chacha20poly1305.h
@@ -47,7 +47,8 @@ int crypto_aead_chacha20poly1305_decrypt(unsigned char *m,
                                          const unsigned char *ad,
                                          unsigned long long adlen,
                                          const unsigned char *npub,
-                                         const unsigned char *k);
+                                         const unsigned char *k)
+            __attribute__ ((warn_unused_result));
 
 #define crypto_aead_chacha20poly1305_IETF_NPUBBYTES 12U
 SODIUM_EXPORT
@@ -73,7 +74,9 @@ int crypto_aead_chacha20poly1305_ietf_decrypt(unsigned char *m,
                                               const unsigned char *ad,
                                               unsigned long long adlen,
                                               const unsigned char *npub,
-                                              const unsigned char *k);
+                                              const unsigned char *k)
+            __attribute__ ((warn_unused_result));
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/libsodium/include/sodium/crypto_auth.h b/src/libsodium/include/sodium/crypto_auth.h
index 1c8d22e7..8fc6bf0e 100644
--- a/src/libsodium/include/sodium/crypto_auth.h
+++ b/src/libsodium/include/sodium/crypto_auth.h
@@ -23,7 +23,8 @@ size_t  crypto_auth_keybytes(void);
 
 #define crypto_auth_PRIMITIVE "hmacsha512256"
 SODIUM_EXPORT
-const char *crypto_auth_primitive(void);
+const char *crypto_auth_primitive(void)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 int crypto_auth(unsigned char *out, const unsigned char *in,
@@ -31,7 +32,9 @@ int crypto_auth(unsigned char *out, const unsigned char *in,
 
 SODIUM_EXPORT
 int crypto_auth_verify(const unsigned char *h, const unsigned char *in,
-                       unsigned long long inlen, const unsigned char *k);
+                       unsigned long long inlen, const unsigned char *k)
+            __attribute__ ((warn_unused_result));
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/libsodium/include/sodium/crypto_auth_hmacsha256.h b/src/libsodium/include/sodium/crypto_auth_hmacsha256.h
index b74e1d7b..1e88112c 100644
--- a/src/libsodium/include/sodium/crypto_auth_hmacsha256.h
+++ b/src/libsodium/include/sodium/crypto_auth_hmacsha256.h
@@ -30,7 +30,8 @@ SODIUM_EXPORT
 int crypto_auth_hmacsha256_verify(const unsigned char *h,
                                   const unsigned char *in,
                                   unsigned long long inlen,
-                                  const unsigned char *k);
+                                  const unsigned char *k)
+            __attribute__ ((warn_unused_result));
 
 /* ------------------------------------------------------------------------- */
 
diff --git a/src/libsodium/include/sodium/crypto_auth_hmacsha512.h b/src/libsodium/include/sodium/crypto_auth_hmacsha512.h
index ff36b9a6..3341b2db 100644
--- a/src/libsodium/include/sodium/crypto_auth_hmacsha512.h
+++ b/src/libsodium/include/sodium/crypto_auth_hmacsha512.h
@@ -30,7 +30,8 @@ SODIUM_EXPORT
 int crypto_auth_hmacsha512_verify(const unsigned char *h,
                                   const unsigned char *in,
                                   unsigned long long inlen,
-                                  const unsigned char *k);
+                                  const unsigned char *k)
+            __attribute__ ((warn_unused_result));
 
 /* ------------------------------------------------------------------------- */
 
diff --git a/src/libsodium/include/sodium/crypto_auth_hmacsha512256.h b/src/libsodium/include/sodium/crypto_auth_hmacsha512256.h
index da05e387..af8018ea 100644
--- a/src/libsodium/include/sodium/crypto_auth_hmacsha512256.h
+++ b/src/libsodium/include/sodium/crypto_auth_hmacsha512256.h
@@ -28,7 +28,8 @@ SODIUM_EXPORT
 int crypto_auth_hmacsha512256_verify(const unsigned char *h,
                                      const unsigned char *in,
                                      unsigned long long inlen,
-                                     const unsigned char *k);
+                                     const unsigned char *k)
+            __attribute__ ((warn_unused_result));
 
 /* ------------------------------------------------------------------------- */
 
diff --git a/src/libsodium/include/sodium/crypto_box.h b/src/libsodium/include/sodium/crypto_box.h
index 827d1095..25b1bfce 100644
--- a/src/libsodium/include/sodium/crypto_box.h
+++ b/src/libsodium/include/sodium/crypto_box.h
@@ -59,7 +59,8 @@ int crypto_box_easy(unsigned char *c, const unsigned char *m,
 SODIUM_EXPORT
 int crypto_box_open_easy(unsigned char *m, const unsigned char *c,
                          unsigned long long clen, const unsigned char *n,
-                         const unsigned char *pk, const unsigned char *sk);
+                         const unsigned char *pk, const unsigned char *sk)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 int crypto_box_detached(unsigned char *c, unsigned char *mac,
@@ -73,7 +74,8 @@ int crypto_box_open_detached(unsigned char *m, const unsigned char *c,
                              unsigned long long clen,
                              const unsigned char *n,
                              const unsigned char *pk,
-                             const unsigned char *sk);
+                             const unsigned char *sk)
+            __attribute__ ((warn_unused_result));
 
 /* -- Precomputation interface -- */
 
@@ -93,7 +95,8 @@ int crypto_box_easy_afternm(unsigned char *c, const unsigned char *m,
 SODIUM_EXPORT
 int crypto_box_open_easy_afternm(unsigned char *m, const unsigned char *c,
                                  unsigned long long clen, const unsigned char *n,
-                                 const unsigned char *k);
+                                 const unsigned char *k)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 int crypto_box_detached_afternm(unsigned char *c, unsigned char *mac,
@@ -104,7 +107,8 @@ SODIUM_EXPORT
 int crypto_box_open_detached_afternm(unsigned char *m, const unsigned char *c,
                                      const unsigned char *mac,
                                      unsigned long long clen, const unsigned char *n,
-                                     const unsigned char *k);
+                                     const unsigned char *k)
+            __attribute__ ((warn_unused_result));
 
 /* -- Ephemeral SK interface -- */
 
@@ -119,7 +123,8 @@ int crypto_box_seal(unsigned char *c, const unsigned char *m,
 SODIUM_EXPORT
 int crypto_box_seal_open(unsigned char *m, const unsigned char *c,
                          unsigned long long clen,
-                         const unsigned char *pk, const unsigned char *sk);
+                         const unsigned char *pk, const unsigned char *sk)
+            __attribute__ ((warn_unused_result));
 
 /* -- NaCl compatibility interface ; Requires padding -- */
 
@@ -139,7 +144,8 @@ int crypto_box(unsigned char *c, const unsigned char *m,
 SODIUM_EXPORT
 int crypto_box_open(unsigned char *m, const unsigned char *c,
                     unsigned long long clen, const unsigned char *n,
-                    const unsigned char *pk, const unsigned char *sk);
+                    const unsigned char *pk, const unsigned char *sk)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 int crypto_box_afternm(unsigned char *c, const unsigned char *m,
@@ -149,7 +155,9 @@ int crypto_box_afternm(unsigned char *c, const unsigned char *m,
 SODIUM_EXPORT
 int crypto_box_open_afternm(unsigned char *m, const unsigned char *c,
                             unsigned long long clen, const unsigned char *n,
-                            const unsigned char *k);
+                            const unsigned char *k)
+            __attribute__ ((warn_unused_result));
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/libsodium/include/sodium/crypto_box_curve25519xsalsa20poly1305.h b/src/libsodium/include/sodium/crypto_box_curve25519xsalsa20poly1305.h
index 865602fa..e58d8a53 100644
--- a/src/libsodium/include/sodium/crypto_box_curve25519xsalsa20poly1305.h
+++ b/src/libsodium/include/sodium/crypto_box_curve25519xsalsa20poly1305.h
@@ -59,7 +59,8 @@ int crypto_box_curve25519xsalsa20poly1305_open(unsigned char *m,
                                                unsigned long long clen,
                                                const unsigned char *n,
                                                const unsigned char *pk,
-                                               const unsigned char *sk);
+                                               const unsigned char *sk)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 int crypto_box_curve25519xsalsa20poly1305_seed_keypair(unsigned char *pk,
@@ -87,7 +88,8 @@ int crypto_box_curve25519xsalsa20poly1305_open_afternm(unsigned char *m,
                                                        const unsigned char *c,
                                                        unsigned long long clen,
                                                        const unsigned char *n,
-                                                       const unsigned char *k);
+                                                       const unsigned char *k)
+            __attribute__ ((warn_unused_result));
 
 #ifdef __cplusplus
 }
diff --git a/src/libsodium/include/sodium/crypto_generichash.h b/src/libsodium/include/sodium/crypto_generichash.h
index 60d46524..c061da12 100644
--- a/src/libsodium/include/sodium/crypto_generichash.h
+++ b/src/libsodium/include/sodium/crypto_generichash.h
@@ -39,7 +39,8 @@ size_t  crypto_generichash_keybytes(void);
 
 #define crypto_generichash_PRIMITIVE "blake2b"
 SODIUM_EXPORT
-const char *crypto_generichash_primitive(void);
+const char *crypto_generichash_primitive(void)
+            __attribute__ ((warn_unused_result));
 
 typedef crypto_generichash_blake2b_state crypto_generichash_state;
 SODIUM_EXPORT
diff --git a/src/libsodium/include/sodium/crypto_hash.h b/src/libsodium/include/sodium/crypto_hash.h
index d455bd51..bc24a78b 100644
--- a/src/libsodium/include/sodium/crypto_hash.h
+++ b/src/libsodium/include/sodium/crypto_hash.h
@@ -30,7 +30,8 @@ int crypto_hash(unsigned char *out, const unsigned char *in,
 
 #define crypto_hash_PRIMITIVE "sha512"
 SODIUM_EXPORT
-const char *crypto_hash_primitive(void);
+const char *crypto_hash_primitive(void)
+            __attribute__ ((warn_unused_result));
 
 #ifdef __cplusplus
 }
diff --git a/src/libsodium/include/sodium/crypto_onetimeauth.h b/src/libsodium/include/sodium/crypto_onetimeauth.h
index 318f672d..5d804bd7 100644
--- a/src/libsodium/include/sodium/crypto_onetimeauth.h
+++ b/src/libsodium/include/sodium/crypto_onetimeauth.h
@@ -35,7 +35,8 @@ int crypto_onetimeauth(unsigned char *out, const unsigned char *in,
 
 SODIUM_EXPORT
 int crypto_onetimeauth_verify(const unsigned char *h, const unsigned char *in,
-                              unsigned long long inlen, const unsigned char *k);
+                              unsigned long long inlen, const unsigned char *k)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 int crypto_onetimeauth_init(crypto_onetimeauth_state *state,
diff --git a/src/libsodium/include/sodium/crypto_onetimeauth_poly1305.h b/src/libsodium/include/sodium/crypto_onetimeauth_poly1305.h
index 835e631b..36b88a56 100644
--- a/src/libsodium/include/sodium/crypto_onetimeauth_poly1305.h
+++ b/src/libsodium/include/sodium/crypto_onetimeauth_poly1305.h
@@ -39,7 +39,8 @@ SODIUM_EXPORT
 int crypto_onetimeauth_poly1305_verify(const unsigned char *h,
                                        const unsigned char *in,
                                        unsigned long long inlen,
-                                       const unsigned char *k);
+                                       const unsigned char *k)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 int crypto_onetimeauth_poly1305_init(crypto_onetimeauth_poly1305_state *state,
diff --git a/src/libsodium/include/sodium/crypto_pwhash_scryptsalsa208sha256.h b/src/libsodium/include/sodium/crypto_pwhash_scryptsalsa208sha256.h
index 0d98e0b2..165f318d 100644
--- a/src/libsodium/include/sodium/crypto_pwhash_scryptsalsa208sha256.h
+++ b/src/libsodium/include/sodium/crypto_pwhash_scryptsalsa208sha256.h
@@ -48,25 +48,29 @@ int crypto_pwhash_scryptsalsa208sha256(unsigned char * const out,
                                        unsigned long long passwdlen,
                                        const unsigned char * const salt,
                                        unsigned long long opslimit,
-                                       size_t memlimit);
+                                       size_t memlimit)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 int crypto_pwhash_scryptsalsa208sha256_str(char out[crypto_pwhash_scryptsalsa208sha256_STRBYTES],
                                            const char * const passwd,
                                            unsigned long long passwdlen,
                                            unsigned long long opslimit,
-                                           size_t memlimit);
+                                           size_t memlimit)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 int crypto_pwhash_scryptsalsa208sha256_str_verify(const char str[crypto_pwhash_scryptsalsa208sha256_STRBYTES],
                                                   const char * const passwd,
-                                                  unsigned long long passwdlen);
+                                                  unsigned long long passwdlen)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 int crypto_pwhash_scryptsalsa208sha256_ll(const uint8_t * passwd, size_t passwdlen,
                                           const uint8_t * salt, size_t saltlen,
                                           uint64_t N, uint32_t r, uint32_t p,
-                                          uint8_t * buf, size_t buflen);
+                                          uint8_t * buf, size_t buflen)
+            __attribute__ ((warn_unused_result));
 
 #ifdef __cplusplus
 }
diff --git a/src/libsodium/include/sodium/crypto_secretbox.h b/src/libsodium/include/sodium/crypto_secretbox.h
index e0d6969e..db68fab1 100644
--- a/src/libsodium/include/sodium/crypto_secretbox.h
+++ b/src/libsodium/include/sodium/crypto_secretbox.h
@@ -37,7 +37,8 @@ int crypto_secretbox_easy(unsigned char *c, const unsigned char *m,
 SODIUM_EXPORT
 int crypto_secretbox_open_easy(unsigned char *m, const unsigned char *c,
                                unsigned long long clen, const unsigned char *n,
-                               const unsigned char *k);
+                               const unsigned char *k)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 int crypto_secretbox_detached(unsigned char *c, unsigned char *mac,
@@ -52,7 +53,8 @@ int crypto_secretbox_open_detached(unsigned char *m,
                                    const unsigned char *mac,
                                    unsigned long long clen,
                                    const unsigned char *n,
-                                   const unsigned char *k);
+                                   const unsigned char *k)
+            __attribute__ ((warn_unused_result));
 
 /* -- NaCl compatibility interface ; Requires padding -- */
 
@@ -72,7 +74,9 @@ int crypto_secretbox(unsigned char *c, const unsigned char *m,
 SODIUM_EXPORT
 int crypto_secretbox_open(unsigned char *m, const unsigned char *c,
                           unsigned long long clen, const unsigned char *n,
-                          const unsigned char *k);
+                          const unsigned char *k)
+            __attribute__ ((warn_unused_result));
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/libsodium/include/sodium/crypto_sign.h b/src/libsodium/include/sodium/crypto_sign.h
index 8b854d37..54a8bb3d 100644
--- a/src/libsodium/include/sodium/crypto_sign.h
+++ b/src/libsodium/include/sodium/crypto_sign.h
@@ -38,7 +38,8 @@ size_t  crypto_sign_secretkeybytes(void);
 
 #define crypto_sign_PRIMITIVE "ed25519"
 SODIUM_EXPORT
-const char *crypto_sign_primitive(void);
+const char *crypto_sign_primitive(void)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 int crypto_sign_seed_keypair(unsigned char *pk, unsigned char *sk,
@@ -55,7 +56,8 @@ int crypto_sign(unsigned char *sm, unsigned long long *smlen_p,
 SODIUM_EXPORT
 int crypto_sign_open(unsigned char *m, unsigned long long *mlen_p,
                      const unsigned char *sm, unsigned long long smlen,
-                     const unsigned char *pk);
+                     const unsigned char *pk)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 int crypto_sign_detached(unsigned char *sig, unsigned long long *siglen_p,
@@ -66,7 +68,9 @@ SODIUM_EXPORT
 int crypto_sign_verify_detached(const unsigned char *sig,
                                 const unsigned char *m,
                                 unsigned long long mlen,
-                                const unsigned char *pk);
+                                const unsigned char *pk)
+            __attribute__ ((warn_unused_result));
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/libsodium/include/sodium/crypto_sign_ed25519.h b/src/libsodium/include/sodium/crypto_sign_ed25519.h
index 5238c2a2..3c55d41d 100644
--- a/src/libsodium/include/sodium/crypto_sign_ed25519.h
+++ b/src/libsodium/include/sodium/crypto_sign_ed25519.h
@@ -35,7 +35,8 @@ int crypto_sign_ed25519(unsigned char *sm, unsigned long long *smlen_p,
 SODIUM_EXPORT
 int crypto_sign_ed25519_open(unsigned char *m, unsigned long long *mlen_p,
                              const unsigned char *sm, unsigned long long smlen,
-                             const unsigned char *pk);
+                             const unsigned char *pk)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 int crypto_sign_ed25519_detached(unsigned char *sig,
@@ -48,7 +49,8 @@ SODIUM_EXPORT
 int crypto_sign_ed25519_verify_detached(const unsigned char *sig,
                                         const unsigned char *m,
                                         unsigned long long mlen,
-                                        const unsigned char *pk);
+                                        const unsigned char *pk)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 int crypto_sign_ed25519_keypair(unsigned char *pk, unsigned char *sk);
@@ -59,7 +61,8 @@ int crypto_sign_ed25519_seed_keypair(unsigned char *pk, unsigned char *sk,
 
 SODIUM_EXPORT
 int crypto_sign_ed25519_pk_to_curve25519(unsigned char *curve25519_pk,
-                                         const unsigned char *ed25519_pk);
+                                         const unsigned char *ed25519_pk)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 int crypto_sign_ed25519_sk_to_curve25519(unsigned char *curve25519_sk,
diff --git a/src/libsodium/include/sodium/crypto_stream.h b/src/libsodium/include/sodium/crypto_stream.h
index b0c6c41a..c4ec4b78 100644
--- a/src/libsodium/include/sodium/crypto_stream.h
+++ b/src/libsodium/include/sodium/crypto_stream.h
@@ -31,7 +31,8 @@ size_t  crypto_stream_noncebytes(void);
 
 #define crypto_stream_PRIMITIVE "xsalsa20"
 SODIUM_EXPORT
-const char *crypto_stream_primitive(void);
+const char *crypto_stream_primitive(void)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 int crypto_stream(unsigned char *c, unsigned long long clen,
diff --git a/src/libsodium/include/sodium/crypto_verify_16.h b/src/libsodium/include/sodium/crypto_verify_16.h
index 7370b15f..5e9eeabe 100644
--- a/src/libsodium/include/sodium/crypto_verify_16.h
+++ b/src/libsodium/include/sodium/crypto_verify_16.h
@@ -13,7 +13,8 @@ SODIUM_EXPORT
 size_t crypto_verify_16_bytes(void);
 
 SODIUM_EXPORT
-int crypto_verify_16(const unsigned char *x, const unsigned char *y);
+int crypto_verify_16(const unsigned char *x, const unsigned char *y)
+            __attribute__ ((warn_unused_result));
 
 #ifdef __cplusplus
 }
diff --git a/src/libsodium/include/sodium/crypto_verify_32.h b/src/libsodium/include/sodium/crypto_verify_32.h
index 58e4d0e8..281b5a1b 100644
--- a/src/libsodium/include/sodium/crypto_verify_32.h
+++ b/src/libsodium/include/sodium/crypto_verify_32.h
@@ -13,7 +13,8 @@ SODIUM_EXPORT
 size_t crypto_verify_32_bytes(void);
 
 SODIUM_EXPORT
-int crypto_verify_32(const unsigned char *x, const unsigned char *y);
+int crypto_verify_32(const unsigned char *x, const unsigned char *y)
+            __attribute__ ((warn_unused_result));
 
 #ifdef __cplusplus
 }
diff --git a/src/libsodium/include/sodium/crypto_verify_64.h b/src/libsodium/include/sodium/crypto_verify_64.h
index 7ed9c89f..0dc7c304 100644
--- a/src/libsodium/include/sodium/crypto_verify_64.h
+++ b/src/libsodium/include/sodium/crypto_verify_64.h
@@ -13,7 +13,8 @@ SODIUM_EXPORT
 size_t crypto_verify_64_bytes(void);
 
 SODIUM_EXPORT
-int crypto_verify_64(const unsigned char *x, const unsigned char *y);
+int crypto_verify_64(const unsigned char *x, const unsigned char *y)
+            __attribute__ ((warn_unused_result));
 
 #ifdef __cplusplus
 }
diff --git a/src/libsodium/include/sodium/randombytes.h b/src/libsodium/include/sodium/randombytes.h
index 08aff052..ea0aef0b 100644
--- a/src/libsodium/include/sodium/randombytes.h
+++ b/src/libsodium/include/sodium/randombytes.h
@@ -44,7 +44,8 @@ SODIUM_EXPORT
 int randombytes_set_implementation(randombytes_implementation *impl);
 
 SODIUM_EXPORT
-const char *randombytes_implementation_name(void);
+const char *randombytes_implementation_name(void)
+            __attribute__ ((warn_unused_result));
 
 /* -- NaCl compatibility interface -- */
 
diff --git a/src/libsodium/include/sodium/randombytes_nativeclient.h b/src/libsodium/include/sodium/randombytes_nativeclient.h
index 07666cb6..03015136 100644
--- a/src/libsodium/include/sodium/randombytes_nativeclient.h
+++ b/src/libsodium/include/sodium/randombytes_nativeclient.h
@@ -17,7 +17,8 @@ SODIUM_EXPORT
 extern struct randombytes_implementation randombytes_nativeclient_implementation;
 
 SODIUM_EXPORT
-const char *randombytes_nativeclient_implementation_name(void);
+const char *randombytes_nativeclient_implementation_name(void)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 uint32_t    randombytes_nativeclient(void);
diff --git a/src/libsodium/include/sodium/randombytes_salsa20_random.h b/src/libsodium/include/sodium/randombytes_salsa20_random.h
index e6d291c5..6bf691e9 100644
--- a/src/libsodium/include/sodium/randombytes_salsa20_random.h
+++ b/src/libsodium/include/sodium/randombytes_salsa20_random.h
@@ -22,7 +22,8 @@ SODIUM_EXPORT
 extern struct randombytes_implementation randombytes_salsa20_implementation;
 
 SODIUM_EXPORT
-const char *randombytes_salsa20_implementation_name(void);
+const char *randombytes_salsa20_implementation_name(void)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 uint32_t    randombytes_salsa20_random(void);
diff --git a/src/libsodium/include/sodium/randombytes_sysrandom.h b/src/libsodium/include/sodium/randombytes_sysrandom.h
index 20dab781..d91da8c9 100644
--- a/src/libsodium/include/sodium/randombytes_sysrandom.h
+++ b/src/libsodium/include/sodium/randombytes_sysrandom.h
@@ -21,7 +21,8 @@ SODIUM_EXPORT
 extern struct randombytes_implementation randombytes_sysrandom_implementation;
 
 SODIUM_EXPORT
-const char *randombytes_sysrandom_implementation_name(void);
+const char *randombytes_sysrandom_implementation_name(void)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 uint32_t    randombytes_sysrandom(void);
diff --git a/src/libsodium/include/sodium/utils.h b/src/libsodium/include/sodium/utils.h
index d837fa42..5e7b49c5 100644
--- a/src/libsodium/include/sodium/utils.h
+++ b/src/libsodium/include/sodium/utils.h
@@ -26,7 +26,8 @@ void sodium_memzero(void * const pnt, const size_t len);
  * This function is not designed for lexicographical comparisons.
  */
 SODIUM_EXPORT
-int sodium_memcmp(const void * const b1_, const void * const b2_, size_t len);
+int sodium_memcmp(const void * const b1_, const void * const b2_, size_t len)
+            __attribute__ ((warn_unused_result));
 
 /*
  * sodium_compare() returns -1 if b1_ < b2_, 1 if b1_ > b2_ and 0 if b1_ == b2_
@@ -36,7 +37,8 @@ int sodium_memcmp(const void * const b1_, const void * const b2_, size_t len);
  */
 SODIUM_EXPORT
 int sodium_compare(const unsigned char *b1_, const unsigned char *b2_,
-                   size_t len);
+                   size_t len)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 void sodium_increment(unsigned char *n, const size_t nlen);
@@ -92,10 +94,12 @@ int sodium_munlock(void * const addr, const size_t len);
  */
 
 SODIUM_EXPORT
-void *sodium_malloc(const size_t size);
+void *sodium_malloc(const size_t size)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
-void *sodium_allocarray(size_t count, size_t size);
+void *sodium_allocarray(size_t count, size_t size)
+            __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
 void sodium_free(void *ptr);
diff --git a/test/default/box_easy2.c b/test/default/box_easy2.c
index d1b6ab40..b0e79de8 100644
--- a/test/default/box_easy2.c
+++ b/test/default/box_easy2.c
@@ -68,9 +68,11 @@ int main(void)
         printf("crypto_box_easy_afternm() with a short ciphertext should have failed\n");
     }
     crypto_box_easy_afternm(c, m, (unsigned long long) mlen, nonce, k1);
-    crypto_box_open_easy_afternm(m2, c,
-                                 (unsigned long long) mlen + crypto_box_MACBYTES,
-                                 nonce, k2);
+    if (crypto_box_open_easy_afternm(m2, c,
+                                     (unsigned long long) mlen + crypto_box_MACBYTES,
+                                 nonce, k2) != 0) {
+        printf("crypto_box_open_easy_afternm() failed\n");
+    }
     printf("%d\n", memcmp(m, m2, mlen));
     if (crypto_box_open_easy_afternm(m2, c, crypto_box_MACBYTES - 1U,
                                      nonce, k2) == 0) {
@@ -79,15 +81,19 @@ int main(void)
     memset(m2, 0, sizeof m2);
     crypto_box_detached(c, mac, m, (unsigned long long) mlen,
                         nonce, alicepk, bobsk);
-    crypto_box_open_detached(m2, c, mac, (unsigned long long) mlen,
-                             nonce, bobpk, alicesk);
+    if (crypto_box_open_detached(m2, c, mac, (unsigned long long) mlen,
+                                 nonce, bobpk, alicesk) != 0) {
+        printf("crypto_box_open_detached() failed\n");
+    }
     printf("%d\n", memcmp(m, m2, mlen));
 
     memset(m2, 0, sizeof m2);
     crypto_box_detached_afternm(c, mac, m, (unsigned long long) mlen,
                                 nonce, k1);
-    crypto_box_open_detached_afternm(m2, c, mac, (unsigned long long) mlen,
-                                     nonce, k2);
+    if (crypto_box_open_detached_afternm(m2, c, mac, (unsigned long long) mlen,
+                                         nonce, k2) != 0) {
+        printf("crypto_box_open_detached_afternm() failed\n");
+    }
     printf("%d\n", memcmp(m, m2, mlen));
 
     sodium_free(alicepk);
diff --git a/test/default/ed25519_convert.c b/test/default/ed25519_convert.c
index 02c0641a..d8625326 100644
--- a/test/default/ed25519_convert.c
+++ b/test/default/ed25519_convert.c
@@ -19,7 +19,9 @@ int main(void)
     unsigned int i;
 
     crypto_sign_ed25519_seed_keypair(ed25519_pk, ed25519_skpk, keypair_seed);
-    crypto_sign_ed25519_pk_to_curve25519(curve25519_pk, ed25519_pk);
+    if (crypto_sign_ed25519_pk_to_curve25519(curve25519_pk, ed25519_pk) != 0) {
+        printf("conversion failed\n");
+    }
     crypto_sign_ed25519_sk_to_curve25519(curve25519_sk, ed25519_skpk);
     sodium_bin2hex(curve25519_pk_hex, sizeof curve25519_pk_hex, curve25519_pk,
                    sizeof curve25519_pk);
@@ -31,7 +33,9 @@ int main(void)
 
     for (i = 0U; i < 500U; i++) {
         crypto_sign_ed25519_keypair(ed25519_pk, ed25519_skpk);
-        crypto_sign_ed25519_pk_to_curve25519(curve25519_pk, ed25519_pk);
+        if (crypto_sign_ed25519_pk_to_curve25519(curve25519_pk, ed25519_pk) != 0) {
+            printf("conversion failed\n");
+        }
         crypto_sign_ed25519_sk_to_curve25519(curve25519_sk, ed25519_skpk);
         crypto_scalarmult_curve25519_base(curve25519_pk2, curve25519_sk);
         if (memcmp(curve25519_pk, curve25519_pk2, sizeof curve25519_pk) != 0) {