diff --git a/bindings/ruby/unicorn_gem/ext/unicorn.c b/bindings/ruby/unicorn_gem/ext/unicorn.c
index bb7363f8..a3509ca4 100644
--- a/bindings/ruby/unicorn_gem/ext/unicorn.c
+++ b/bindings/ruby/unicorn_gem/ext/unicorn.c
@@ -31,7 +31,7 @@ VALUE SavedContext = Qnil;
 VALUE Hook = Qnil;
 
 
-void Init_unicorn_engine() {
+void Init_unicorn_engine(void) {
     rb_require("unicorn_engine/unicorn_const");
     UnicornModule = rb_define_module("UnicornEngine");
     UcError = rb_define_class_under(UnicornModule, "UcError", rb_eStandardError);
diff --git a/samples/mem_apis.c b/samples/mem_apis.c
index 57756f3c..37f04019 100644
--- a/samples/mem_apis.c
+++ b/samples/mem_apis.c
@@ -193,7 +193,7 @@ static void do_nx_demo(bool cause_fault)
     uc_close(uc);
 }
 
-static void nx_test()
+static void nx_test(void)
 {
     printf("NX demo - step 1: show that code runs to completion\n");
     do_nx_demo(false);
@@ -276,7 +276,7 @@ static void do_perms_demo(bool change_perms)
     uc_close(uc);
 }
 
-static void perms_test()
+static void perms_test(void)
 {
     printf("Permissions demo - step 1: show that area is writeable\n");
     do_perms_demo(false);
@@ -355,7 +355,7 @@ static void do_unmap_demo(bool do_unmap)
     uc_close(uc);
 }
 
-static void unmap_test()
+static void unmap_test(void)
 {
     printf("Unmap demo - step 1: show that area is writeable\n");
     do_unmap_demo(false);
diff --git a/samples/sample_arm.c b/samples/sample_arm.c
index 8635a9e8..95bcf6cb 100644
--- a/samples/sample_arm.c
+++ b/samples/sample_arm.c
@@ -366,7 +366,7 @@ static void test_thumb_ite_internal(bool step, uint32_t *r2_out,
     *r3_out = r3;
 }
 
-static void test_thumb_ite()
+static void test_thumb_ite(void)
 {
     uint32_t r2, r3;
     uint32_t step_r2, step_r3;
@@ -390,7 +390,7 @@ static void test_thumb_ite()
     }
 }
 
-static void test_read_sctlr()
+static void test_read_sctlr(void)
 {
     uc_engine *uc;
     uc_err err;
diff --git a/samples/sample_arm64.c b/samples/sample_arm64.c
index 84f32c29..603b59cf 100644
--- a/samples/sample_arm64.c
+++ b/samples/sample_arm64.c
@@ -197,7 +197,7 @@ static void test_arm64eb(void)
     uc_close(uc);
 }
 
-static void test_arm64_sctlr()
+static void test_arm64_sctlr(void)
 {
     uc_engine *uc;
     uc_err err;
@@ -248,7 +248,7 @@ static uint32_t hook_mrs(uc_engine *uc, uc_arm64_reg reg,
     return 1;
 }
 
-static void test_arm64_hook_mrs()
+static void test_arm64_hook_mrs(void)
 {
     uc_engine *uc;
     uc_err err;
diff --git a/samples/sample_batch_reg.c b/samples/sample_batch_reg.c
index 8b5736f4..7124b8b8 100644
--- a/samples/sample_batch_reg.c
+++ b/samples/sample_batch_reg.c
@@ -49,7 +49,7 @@ void hook_code(uc_engine *uc, uint64_t addr, uint32_t size, void *user_data)
     printf("HOOK_CODE: 0x%" PRIx64 ", 0x%x\n", addr, size);
 }
 
-int main()
+int main(void)
 {
     int i;
     uc_hook sys_hook;
diff --git a/samples/sample_ctl.c b/samples/sample_ctl.c
index 0b1b5898..9a81e3df 100644
--- a/samples/sample_ctl.c
+++ b/samples/sample_ctl.c
@@ -79,7 +79,7 @@ static void trace_new_edge(uc_engine *uc, uc_tb *cur, uc_tb *prev, void *data)
            prev->pc + prev->size - 1, cur->pc);
 }
 
-void test_uc_ctl_exits()
+void test_uc_ctl_exits(void)
 {
     uc_engine *uc;
     uc_err err;
@@ -193,7 +193,7 @@ double time_emulation(uc_engine *uc, uint64_t start, uint64_t end)
     return (t2 - t1) * 1000.0 / CLOCKS_PER_SEC;
 }
 
-static void test_uc_ctl_tb_cache()
+static void test_uc_ctl_tb_cache(void)
 {
     uc_engine *uc;
     uc_err err;
diff --git a/samples/sample_x86.c b/samples/sample_x86.c
index 735a9985..a3ce01b2 100644
--- a/samples/sample_x86.c
+++ b/samples/sample_x86.c
@@ -1240,7 +1240,7 @@ static void test_i386_invalid_mem_read_in_tb(void)
     uc_close(uc);
 }
 
-static void test_i386_smc_xor()
+static void test_i386_smc_xor(void)
 {
     uc_engine *uc;
     uc_err err;
@@ -1319,7 +1319,7 @@ static void mmio_write_callback(uc_engine *uc, uint64_t offset, unsigned size,
     return;
 }
 
-static void test_i386_mmio()
+static void test_i386_mmio(void)
 {
     uc_engine *uc;
     int r_ecx = 0xdeadbeef;
@@ -1392,7 +1392,7 @@ static bool test_i386_hook_mem_invalid_cb(uc_engine *uc, uc_mem_type type,
     return true;
 }
 
-static void test_i386_hook_mem_invalid()
+static void test_i386_hook_mem_invalid(void)
 {
     uc_engine *uc;
     uc_hook hook;
diff --git a/samples/sample_x86_32_gdt_and_seg_regs.c b/samples/sample_x86_32_gdt_and_seg_regs.c
index 1ffd8892..723b1f5c 100644
--- a/samples/sample_x86_32_gdt_and_seg_regs.c
+++ b/samples/sample_x86_32_gdt_and_seg_regs.c
@@ -163,7 +163,7 @@ static void hex_dump(unsigned char *ptr, unsigned int len)
 }
 */
 
-static void gdt_demo()
+static void gdt_demo(void)
 {
     uc_engine *uc;
     uc_hook hook1, hook2;
diff --git a/tests/regress/00opcode_uc_crash.c b/tests/regress/00opcode_uc_crash.c
index e735cfef..92cf350d 100644
--- a/tests/regress/00opcode_uc_crash.c
+++ b/tests/regress/00opcode_uc_crash.c
@@ -7,7 +7,7 @@
 #define X86_CODE32 "\x00" // add byte ptr ds:[eax],al
 #define ADDRESS 0x1000000
 
-static void VM_exec()
+static void VM_exec(void)
 {
     uc_engine *uc;
     uc_err err;
diff --git a/tests/regress/arm_enable_vfp.c b/tests/regress/arm_enable_vfp.c
index aebcd983..a1c5500d 100644
--- a/tests/regress/arm_enable_vfp.c
+++ b/tests/regress/arm_enable_vfp.c
@@ -6,7 +6,7 @@
 #define ADDRESS 0x1000
 #define ARM_VMOV "\xC0\xEF\x10\x00" // VMOV.I32 D16, #0 ; Vector Move
 
-int main()
+int main(void)
 {
     uc_engine *uc;
     uc_err err;
diff --git a/tests/regress/block_test.c b/tests/regress/block_test.c
index 5af825f3..48666603 100644
--- a/tests/regress/block_test.c
+++ b/tests/regress/block_test.c
@@ -24,7 +24,7 @@ void cb_hookblock(uc_engine *uc, uint64_t address, uint32_t size, void *user_dat
    fprintf(stderr, "ok %d - basic block size is correct\n", count++);
 }
 
-int main() {
+int main(void) {
    uc_engine *uc;
 
    fprintf(stderr, "# basic block callback test\n");
diff --git a/tests/regress/eflags_noset.c b/tests/regress/eflags_noset.c
index 7f1b9710..e3a105bd 100644
--- a/tests/regress/eflags_noset.c
+++ b/tests/regress/eflags_noset.c
@@ -20,7 +20,7 @@ typedef uint64_t puint;
 #define PRIX3264 PRIX64
 #endif
 
-uint32_t realEflags()
+uint32_t realEflags(void)
 {
     puint val = 0;
 
@@ -55,7 +55,7 @@ uint32_t realEflags()
     return (uint32_t)val & 0xFFFFFFFF;
 }
 
-static void VM_exec()
+static void VM_exec(void)
 {
 #if defined(__i386__) || defined(__x86_64__)
     uc_engine *uc;
diff --git a/tests/regress/eflags_nosync.c b/tests/regress/eflags_nosync.c
index 37b79504..398608e1 100644
--- a/tests/regress/eflags_nosync.c
+++ b/tests/regress/eflags_nosync.c
@@ -64,7 +64,7 @@ static bool hook_invalid_mem(uc_engine *uc, uc_mem_type type, uint64_t address,
     }
 }
 
-static void VM_exec()
+static void VM_exec(void)
 {
     uc_engine *uc;
     uc_err err;
diff --git a/tests/regress/emu_clear_errors.c b/tests/regress/emu_clear_errors.c
index 7f03ec37..3dda86a9 100644
--- a/tests/regress/emu_clear_errors.c
+++ b/tests/regress/emu_clear_errors.c
@@ -38,7 +38,7 @@ bool cb_hookunmapped(uc_engine *uc, uc_mem_type type, uint64_t address, uint32_t
              "\x56" \
              "\xFF\x15\x20\x20\x00\x10"
 
-int main() {
+int main(void) {
    uc_engine *uc;
 
    uc_err err = uc_open(UC_ARCH_X86, UC_MODE_32, &uc);
diff --git a/tests/regress/hook_extrainvoke.c b/tests/regress/hook_extrainvoke.c
index 8fd486f1..54197459 100644
--- a/tests/regress/hook_extrainvoke.c
+++ b/tests/regress/hook_extrainvoke.c
@@ -14,7 +14,7 @@ void hook_ins(uc_engine *uc, uint64_t address, uint32_t size, void *user_data)
     printf("hook called\n");
 }
 
-static void VM_exec()
+static void VM_exec(void)
 {
     uc_engine *uc;
     uc_err err;
diff --git a/tests/regress/map_crash.c b/tests/regress/map_crash.c
index 1d89d8dd..69a2280c 100644
--- a/tests/regress/map_crash.c
+++ b/tests/regress/map_crash.c
@@ -6,7 +6,7 @@
 #define UC_BUG_WRITE_SIZE 13000
 #define UC_BUG_WRITE_ADDR 0x1000
 
-int main()
+int main(void)
 {
     int size;
     uint8_t *buf;
diff --git a/tests/regress/map_write.c b/tests/regress/map_write.c
index 124e2d82..ef71b2ea 100644
--- a/tests/regress/map_write.c
+++ b/tests/regress/map_write.c
@@ -6,7 +6,7 @@
 #define SIZE 1024*64
 #define OVERFLOW 1
 
-int main()
+int main(void)
 {
     uc_engine *uc = NULL;
     uint8_t *buf = NULL, *buf2 = NULL;
diff --git a/tests/regress/mips_kseg0_1.c b/tests/regress/mips_kseg0_1.c
index be47bf50..7b650ef6 100644
--- a/tests/regress/mips_kseg0_1.c
+++ b/tests/regress/mips_kseg0_1.c
@@ -20,7 +20,7 @@
 
 #define MIPS_CODE_EL "\x56\x34\x21\x34" // ori $at, $at, 0x3456;
 
-int main() 
+int main(void)
 {
 
     uc_engine *uc;
diff --git a/tests/regress/sigill.c b/tests/regress/sigill.c
index 9e5061d3..d92bfa6e 100644
--- a/tests/regress/sigill.c
+++ b/tests/regress/sigill.c
@@ -16,7 +16,7 @@ void _interrupt(uc_engine *uc, uint32_t intno, void *user_data)
     }
 }
 
-int main()
+int main(void)
 {
     int size;
     uint8_t *buf;
diff --git a/tests/regress/sigill2.c b/tests/regress/sigill2.c
index 8e6ad560..5a56171b 100644
--- a/tests/regress/sigill2.c
+++ b/tests/regress/sigill2.c
@@ -6,7 +6,7 @@
 #define UC_BUG_WRITE_SIZE 128
 #define UC_BUG_WRITE_ADDR 0x2000
 
-int main()
+int main(void)
 {
     int size;
     uc_engine *uc;