diff --git a/src/api/api_ast.cpp b/src/api/api_ast.cpp
index 404d9d9ac..81a716b12 100644
--- a/src/api/api_ast.cpp
+++ b/src/api/api_ast.cpp
@@ -38,6 +38,8 @@ Revision History:
 #include"scoped_timer.h"
 #include"pp_params.hpp"
 
+extern bool is_numeral_sort(Z3_context c, Z3_sort ty);
+
 extern "C" {
 
     Z3_symbol Z3_API Z3_mk_int_symbol(Z3_context c, int i) {
@@ -313,8 +315,6 @@ extern "C" {
         Z3_CATCH_RETURN("");
     }
 
-    extern bool is_numeral_sort(Z3_context c, Z3_sort ty);
-    
     Z3_ast_kind Z3_API Z3_get_ast_kind(Z3_context c, Z3_ast a) {
         Z3_TRY;
         LOG_Z3_get_ast_kind(c, a);
diff --git a/src/api/api_config_params.cpp b/src/api/api_config_params.cpp
index aaaabb7b2..48c2df4a9 100644
--- a/src/api/api_config_params.cpp
+++ b/src/api/api_config_params.cpp
@@ -43,7 +43,7 @@ extern "C" {
         }
     }
 
-    void Z3_API Z3_global_param_reset_all() {
+    void Z3_API Z3_global_param_reset_all(void) {
         memory::initialize(UINT_MAX);
         LOG_Z3_global_param_reset_all();
         gparams::reset();
@@ -71,7 +71,7 @@ extern "C" {
         }
     }
 
-    Z3_config Z3_API Z3_mk_config() {
+    Z3_config Z3_API Z3_mk_config(void) {
         memory::initialize(UINT_MAX);
         LOG_Z3_mk_config();
         Z3_config r = reinterpret_cast<Z3_config>(alloc(context_params));
diff --git a/src/api/api_log.cpp b/src/api/api_log.cpp
index 84c262a96..4a1ae27e5 100644
--- a/src/api/api_log.cpp
+++ b/src/api/api_log.cpp
@@ -44,7 +44,7 @@ extern "C" {
         _Z3_append_log(static_cast<char const *>(str));
     }
 
-    void Z3_API Z3_close_log() {
+    void Z3_API Z3_close_log(void) {
         if (g_z3_log != 0) {
             dealloc(g_z3_log);
             g_z3_log_enabled = false;
diff --git a/src/api/api_numeral.cpp b/src/api/api_numeral.cpp
index 2660d9a01..d4a6587bc 100644
--- a/src/api/api_numeral.cpp
+++ b/src/api/api_numeral.cpp
@@ -24,27 +24,27 @@ Revision History:
 #include"bv_decl_plugin.h"
 #include"algebraic_numbers.h"
 
+bool is_numeral_sort(Z3_context c, Z3_sort ty) {
+    sort * _ty = to_sort(ty);
+    family_id fid  = _ty->get_family_id();
+    if (fid != mk_c(c)->get_arith_fid() && 
+        fid != mk_c(c)->get_bv_fid() &&
+        fid != mk_c(c)->get_datalog_fid()) {
+        return false;
+    }
+    return true;
+}
+
+bool check_numeral_sort(Z3_context c, Z3_sort ty) {
+    bool is_num = is_numeral_sort(c, ty);
+    if (!is_num) {
+        SET_ERROR_CODE(Z3_INVALID_ARG);
+    }
+    return is_num;
+}
+
 extern "C" {
 
-    bool is_numeral_sort(Z3_context c, Z3_sort ty) {
-        sort * _ty = to_sort(ty);
-        family_id fid  = _ty->get_family_id();
-        if (fid != mk_c(c)->get_arith_fid() && 
-            fid != mk_c(c)->get_bv_fid() &&
-            fid != mk_c(c)->get_datalog_fid()) {
-            return false;
-        }
-        return true;
-    }
-
-    bool check_numeral_sort(Z3_context c, Z3_sort ty) {
-        bool is_num = is_numeral_sort(c, ty);
-        if (!is_num) {
-            SET_ERROR_CODE(Z3_INVALID_ARG);
-        }
-        return is_num;
-    }
-
     Z3_ast Z3_API Z3_mk_numeral(Z3_context c, const char* n, Z3_sort ty) {
         Z3_TRY;
         LOG_Z3_mk_numeral(c, n, ty);
diff --git a/src/api/z3_api.h b/src/api/z3_api.h
index 410945235..ea3b05e40 100644
--- a/src/api/z3_api.h
+++ b/src/api/z3_api.h
@@ -1274,7 +1274,7 @@ extern "C" {
 
        def_API('Z3_global_param_reset_all', VOID, ())
     */
-    void Z3_API Z3_global_param_reset_all();
+    void Z3_API Z3_global_param_reset_all(void);
     
     /**
        \brief Get a global (or module) parameter.
@@ -1335,7 +1335,7 @@ extern "C" {
 
        def_API('Z3_mk_config', CONFIG, ())
     */
-    Z3_config Z3_API Z3_mk_config();
+    Z3_config Z3_API Z3_mk_config(void);
 
     /**
        \brief Delete the given configuration object.
@@ -4765,7 +4765,7 @@ END_MLAPI_EXCLUDE
 
        extra_API('Z3_close_log', VOID, ())
     */
-    void Z3_API Z3_close_log();
+    void Z3_API Z3_close_log(void);
 
     /**
        \brief Enable/disable printing warning messages to the console.