diff --git a/crypto/ec/ecp_nistp224.c b/crypto/ec/ecp_nistp224.c
index 6e7c687c43c884f85781a9a9bf0cbf900fdec7bf..6155b546df8bb1cb190466af167e27775749d46d 100644
--- a/crypto/ec/ecp_nistp224.c
+++ b/crypto/ec/ecp_nistp224.c
@@ -1212,7 +1212,7 @@ static void batch_mul(felem x_out, felem y_out, felem z_out,
  * FUNCTIONS TO MANAGE PRECOMPUTATION
  */
 
-static NISTP224_PRE_COMP *nistp224_pre_comp_new()
+static NISTP224_PRE_COMP *nistp224_pre_comp_new(void)
 {
     NISTP224_PRE_COMP *ret = OPENSSL_zalloc(sizeof(*ret));
 
diff --git a/crypto/ec/ecp_nistp256.c b/crypto/ec/ecp_nistp256.c
index 19caa031c8546c300b8ea5cd569d7bda6f4e2d98..00fcfd5bbd7e7b40fa0f9f2d821098d14f683c2b 100644
--- a/crypto/ec/ecp_nistp256.c
+++ b/crypto/ec/ecp_nistp256.c
@@ -1832,7 +1832,7 @@ const EC_METHOD *EC_GFp_nistp256_method(void)
  * FUNCTIONS TO MANAGE PRECOMPUTATION
  */
 
-static NISTP256_PRE_COMP *nistp256_pre_comp_new()
+static NISTP256_PRE_COMP *nistp256_pre_comp_new(void)
 {
     NISTP256_PRE_COMP *ret = OPENSSL_zalloc(sizeof(*ret));
 
diff --git a/crypto/ec/ecp_nistp521.c b/crypto/ec/ecp_nistp521.c
index 43f3e2d9eef34ac601ea1732157b69828960128d..4e6c0f98fbc7943ef9a4a27a9f119f544d060951 100644
--- a/crypto/ec/ecp_nistp521.c
+++ b/crypto/ec/ecp_nistp521.c
@@ -1671,7 +1671,7 @@ const EC_METHOD *EC_GFp_nistp521_method(void)
  * FUNCTIONS TO MANAGE PRECOMPUTATION
  */
 
-static NISTP521_PRE_COMP *nistp521_pre_comp_new()
+static NISTP521_PRE_COMP *nistp521_pre_comp_new(void)
 {
     NISTP521_PRE_COMP *ret = OPENSSL_zalloc(sizeof(*ret));
 
diff --git a/engines/e_padlock.c b/engines/e_padlock.c
index b86f16550448130c2350dcdee7322872165bf124..43944abc42c39f28cc9633f8a3c7da1ff18d619f 100644
--- a/engines/e_padlock.c
+++ b/engines/e_padlock.c
@@ -199,10 +199,10 @@ struct padlock_cipher_data {
 };
 
 /* Interface to assembler module */
-unsigned int padlock_capability();
+unsigned int padlock_capability(void);
 void padlock_key_bswap(AES_KEY *key);
 void padlock_verify_context(struct padlock_cipher_data *ctx);
-void padlock_reload_key();
+void padlock_reload_key(void);
 void padlock_aes_block(void *out, const void *inp,
                        struct padlock_cipher_data *ctx);
 int padlock_ecb_encrypt(void *out, const void *inp,
diff --git a/test/ectest.c b/test/ectest.c
index 73e8aa8732bdd14dbd46f584dcb89f0e121bddf5..ead23d72302d28a9a89fbca4615ad6126acac0b5 100644
--- a/test/ectest.c
+++ b/test/ectest.c
@@ -1167,7 +1167,7 @@ static int internal_curve_test_method(int n)
  * implementations of several NIST curves with characteristic > 3.
  */
 struct nistp_test_params {
-    const EC_METHOD *(*meth) ();
+    const EC_METHOD *(*meth) (void);
     int degree;
     /*
      * Qx, Qy and D are taken from