diff --git a/src/arm/midr.c b/src/arm/midr.c
index f75ea8b..374e90a 100644
--- a/src/arm/midr.c
+++ b/src/arm/midr.c
@@ -141,7 +141,7 @@ void init_cpu_info(struct cpuInfo* cpu) {
 // true...
 // ARM32 https://elixir.bootlin.com/linux/latest/source/arch/arm/include/uapi/asm/hwcap.h
 // ARM64 https://elixir.bootlin.com/linux/latest/source/arch/arm64/include/uapi/asm/hwcap.h
-struct features* get_features_info() {
+struct features* get_features_info(void) {
   struct features* feat = emalloc(sizeof(struct features));
   bool *ptr = &(feat->AES);
   for(uint32_t i = 0; i < sizeof(struct features)/sizeof(bool); i++, ptr++) {
@@ -371,7 +371,7 @@ struct cpuInfo* get_cpu_info_mach(struct cpuInfo* cpu) {
 }
 #endif
 
-struct cpuInfo* get_cpu_info() {
+struct cpuInfo* get_cpu_info(void) {
   struct cpuInfo* cpu = malloc(sizeof(struct cpuInfo));
   init_cpu_info(cpu);
 
diff --git a/src/arm/midr.h b/src/arm/midr.h
index 9da3bb6..a133ca0 100644
--- a/src/arm/midr.h
+++ b/src/arm/midr.h
@@ -3,7 +3,7 @@
 
 #include "../common/cpu.h"
 
-struct cpuInfo* get_cpu_info();
+struct cpuInfo* get_cpu_info(void);
 
 uint32_t get_nsockets(struct topology* topo);
 char* get_str_topology(struct cpuInfo* cpu, struct topology* topo, bool dual_socket);
diff --git a/src/arm/soc.c b/src/arm/soc.c
index 3a5c975..fa3d6f2 100644
--- a/src/arm/soc.c
+++ b/src/arm/soc.c
@@ -702,7 +702,7 @@ struct system_on_chip* guess_soc_apple(struct system_on_chip* soc) {
 }
 #endif
 
-struct system_on_chip* get_soc() {
+struct system_on_chip* get_soc(void) {
   struct system_on_chip* soc = emalloc(sizeof(struct system_on_chip));
   soc->raw_name = NULL;
   soc->soc_vendor = SOC_VENDOR_UNKNOWN;
diff --git a/src/arm/soc.h b/src/arm/soc.h
index 257fc4a..5a0aae7 100644
--- a/src/arm/soc.h
+++ b/src/arm/soc.h
@@ -25,7 +25,7 @@ struct system_on_chip {
   char* raw_name;    
 };
 
-struct system_on_chip* get_soc();
+struct system_on_chip* get_soc(void);
 char* get_soc_name(struct system_on_chip* soc);
 VENDOR get_soc_vendor(struct system_on_chip* soc);
 char* get_str_process(struct system_on_chip* soc);
diff --git a/src/arm/udev.c b/src/arm/udev.c
index 98c06b9..1fe0a1b 100644
--- a/src/arm/udev.c
+++ b/src/arm/udev.c
@@ -129,15 +129,15 @@ char* get_field_from_cpuinfo(char* CPUINFO_FIELD) {
   return hardware;
 }
 
-char* get_hardware_from_cpuinfo() {
+char* get_hardware_from_cpuinfo(void) {
   return get_field_from_cpuinfo(CPUINFO_HARDWARE_STR);
 }
 
-char* get_revision_from_cpuinfo() {
+char* get_revision_from_cpuinfo(void) {
   return get_field_from_cpuinfo(CPUINFO_REVISION_STR);
 }
 
-bool is_raspberry_pi() {
+bool is_raspberry_pi(void) {
   int filelen;
   char* buf;
   if((buf = read_file(_PATH_DEVICETREE_MODEL, &filelen)) == NULL) {
diff --git a/src/arm/udev.h b/src/arm/udev.h
index f3c52a0..e6ef072 100644
--- a/src/arm/udev.h
+++ b/src/arm/udev.h
@@ -4,11 +4,11 @@
 #include "../common/udev.h"
 
 #define UNKNOWN -1
-int get_ncores_from_cpuinfo();
+int get_ncores_from_cpuinfo(void);
 uint32_t get_midr_from_cpuinfo(uint32_t core, bool* success);
-char* get_hardware_from_cpuinfo();
-char* get_revision_from_cpuinfo();
-bool is_raspberry_pi();
+char* get_hardware_from_cpuinfo(void);
+char* get_revision_from_cpuinfo(void);
+bool is_raspberry_pi(void);
 
 #endif
 
diff --git a/src/common/args.c b/src/common/args.c
index 475855e..7da6194 100644
--- a/src/common/args.c
+++ b/src/common/args.c
@@ -71,59 +71,59 @@ const char *args_str[] = {
 
 static struct args_struct args;
 
-STYLE get_style() {
+STYLE get_style(void) {
   return args.style;
 }
 
-struct color** get_colors() {
+struct color** get_colors(void) {
   return args.colors;
 }
 
-bool show_help() {
+bool show_help(void) {
   return args.help_flag;
 }
 
-bool show_version() {
+bool show_version(void) {
   return args.version_flag;
 }
 
-bool show_debug() {
+bool show_debug(void) {
   return args.debug_flag;
 }
 
-bool show_raw() {
+bool show_raw(void) {
   return args.raw_flag;
 }
 
-bool accurate_pp() {
+bool accurate_pp(void) {
   return args.accurate_pp;
 }
 
-bool show_full_cpu_name() {
+bool show_full_cpu_name(void) {
   return args.full_cpu_name_flag;
 }
 
-bool show_logo_long() {
+bool show_logo_long(void) {
   return args.logo_long;
 }
 
-bool show_logo_short() {
+bool show_logo_short(void) {
   return args.logo_short;
 }
 
-bool show_logo_intel_new() {
+bool show_logo_intel_new(void) {
   return args.logo_intel_new;
 }
 
-bool show_logo_intel_old() {
+bool show_logo_intel_old(void) {
   return args.logo_intel_old;
 }
 
-bool verbose_enabled() {
+bool verbose_enabled(void) {
   return args.verbose_flag;
 }
 
-int max_arg_str_length() {
+int max_arg_str_length(void) {
   int max_len = -1;
   int len = sizeof(args_str) / sizeof(args_str[0]);
   for(int i=0; i < len; i++) {
@@ -211,7 +211,7 @@ bool parse_color(char* optarg_str, struct color*** cs) {
   return true;
 }
 
-char* build_short_options() {
+char* build_short_options(void) {
   const char *c = args_chr;
   int len = sizeof(args_chr) / sizeof(args_chr[0]);
   char* str = (char *) emalloc(sizeof(char) * (len*2 + 1));
diff --git a/src/common/args.h b/src/common/args.h
index 7e7c3a9..116c178 100644
--- a/src/common/args.h
+++ b/src/common/args.h
@@ -39,21 +39,21 @@ extern const char *args_str[];
 
 #include "printer.h"
 
-int max_arg_str_length();
+int max_arg_str_length(void);
 bool parse_args(int argc, char* argv[]);
-bool show_help();
-bool accurate_pp();
-bool show_full_cpu_name();
-bool show_logo_long();
-bool show_logo_short();
-bool show_logo_intel_new();
-bool show_logo_intel_old();
-bool show_raw();
-bool show_debug();
-bool show_version();
-bool verbose_enabled();
+bool show_help(void);
+bool accurate_pp(void);
+bool show_full_cpu_name(void);
+bool show_logo_long(void);
+bool show_logo_short(void);
+bool show_logo_intel_new(void);
+bool show_logo_intel_old(void);
+bool show_raw(void);
+bool show_debug(void);
+bool show_version(void);
+bool verbose_enabled(void);
 void free_colors_struct(struct color** cs);
-struct color** get_colors();
-STYLE get_style();
+struct color** get_colors(void);
+STYLE get_style(void);
 
 #endif
diff --git a/src/common/printer.c b/src/common/printer.c
index c0e581f..16c58d2 100644
--- a/src/common/printer.c
+++ b/src/common/printer.c
@@ -909,7 +909,7 @@ bool print_cpufetch_arm(struct cpuInfo* cpu, STYLE s, struct color** cs, struct
 }
 #endif
 
-struct terminal* get_terminal_size() {
+struct terminal* get_terminal_size(void) {
   struct terminal* term = emalloc(sizeof(struct terminal));
 
 #ifdef _WIN32
diff --git a/src/common/udev.c b/src/common/udev.c
index 1f14c4c..66c1d52 100644
--- a/src/common/udev.c
+++ b/src/common/udev.c
@@ -3,7 +3,7 @@
 #include "cpu.h"
 
 // https://www.kernel.org/doc/html/latest/core-api/cpu_hotplug.html
-int get_ncores_from_cpuinfo() {
+int get_ncores_from_cpuinfo(void) {
   // Examples:
   // 0-271
   // 0-7
diff --git a/src/common/udev.h b/src/common/udev.h
index ece967c..bf83493 100644
--- a/src/common/udev.h
+++ b/src/common/udev.h
@@ -36,6 +36,6 @@ long get_l1d_cache_size(uint32_t core);
 long get_l2_cache_size(uint32_t core);
 long get_l3_cache_size(uint32_t core);
 int get_num_caches_by_level(struct cpuInfo* cpu, uint32_t level);
-int get_ncores_from_cpuinfo();
+int get_ncores_from_cpuinfo(void);
 
 #endif
diff --git a/src/ppc/ppc.c b/src/ppc/ppc.c
index 1a5d3d9..50b0897 100644
--- a/src/ppc/ppc.c
+++ b/src/ppc/ppc.c
@@ -111,7 +111,7 @@ struct topology* get_topology_info(struct cache* cach) {
   return topo;
 }
 
-static inline uint32_t mfpvr() {
+static inline uint32_t mfpvr(void) {
     uint32_t pvr;
 
     asm ("mfpvr %0"
@@ -123,7 +123,7 @@ struct uarch* get_cpu_uarch(struct cpuInfo* cpu) {
   return get_uarch_from_pvr(cpu->pvr);
 }
 
-struct frequency* get_frequency_info() {
+struct frequency* get_frequency_info(void) {
   struct frequency* freq = emalloc(sizeof(struct frequency));
 
   freq->max = get_max_freq_from_file(0);
@@ -158,7 +158,7 @@ int64_t get_peak_performance(struct cpuInfo* cpu, struct topology* topo, int64_t
   return flops;
 }
 
-struct cpuInfo* get_cpu_info() {
+struct cpuInfo* get_cpu_info(void) {
   struct cpuInfo* cpu = emalloc(sizeof(struct cpuInfo));
   struct features* feat = emalloc(sizeof(struct features));
   cpu->feat = feat;
diff --git a/src/ppc/ppc.h b/src/ppc/ppc.h
index 87e8af2..7b827b1 100644
--- a/src/ppc/ppc.h
+++ b/src/ppc/ppc.h
@@ -3,7 +3,7 @@
 
 #include "../common/cpu.h"
 
-struct cpuInfo* get_cpu_info();
+struct cpuInfo* get_cpu_info(void);
 char* get_str_altivec(struct cpuInfo* cpu);
 char* get_str_topology(struct topology* topo, bool dual_socket);
 void print_debug(struct cpuInfo* cpu);
diff --git a/src/x86/cpuid.c b/src/x86/cpuid.c
index fdc8869..bbbcbac 100644
--- a/src/x86/cpuid.c
+++ b/src/x86/cpuid.c
@@ -70,7 +70,7 @@ void get_name_cpuid(char* name, uint32_t reg1, uint32_t reg2, uint32_t reg3) {
   name[c++] = (reg3>>24) & MASK;
 }
 
-char* get_str_cpu_name_internal() {
+char* get_str_cpu_name_internal(void) {
   uint32_t eax = 0;
   uint32_t ebx = 0;
   uint32_t ecx = 0;
@@ -412,7 +412,7 @@ bool set_cpu_module(int m, int total_modules, int32_t* first_core) {
   return true;
 }
 
-int32_t get_core_type() {
+int32_t get_core_type(void) {
   uint32_t eax = 0x0000001A;
   uint32_t ebx = 0;
   uint32_t ecx = 0;
@@ -430,7 +430,7 @@ int32_t get_core_type() {
   }
 }
 
-struct cpuInfo* get_cpu_info() {
+struct cpuInfo* get_cpu_info(void) {
   struct cpuInfo* cpu = emalloc(sizeof(struct cpuInfo));
   cpu->peak_performance = -1;
   cpu->next_cpu = NULL;
diff --git a/src/x86/cpuid.h b/src/x86/cpuid.h
index 3b0e21b..a0a6a5c 100644
--- a/src/x86/cpuid.h
+++ b/src/x86/cpuid.h
@@ -3,7 +3,7 @@
 
 #include "../common/cpu.h"
 
-struct cpuInfo* get_cpu_info();
+struct cpuInfo* get_cpu_info(void);
 struct cache* get_cache_info(struct cpuInfo* cpu);
 struct frequency* get_frequency_info(struct cpuInfo* cpu);
 struct topology* get_topology_info(struct cpuInfo* cpu, struct cache* cach, int module);
diff --git a/src/x86/freq/freq_avx.c b/src/x86/freq/freq_avx.c
index 29bf667..04354eb 100644
--- a/src/x86/freq/freq_avx.c
+++ b/src/x86/freq/freq_avx.c
@@ -10,7 +10,7 @@
 #include <stdint.h>
 #include "freq.h"
 
-void* compute_avx() {
+void* compute_avx(void) {
   bool end = false;
 
   struct timeval begin, now;
diff --git a/src/x86/freq/freq_avx.h b/src/x86/freq/freq_avx.h
index 5a3de14..43858d1 100644
--- a/src/x86/freq/freq_avx.h
+++ b/src/x86/freq/freq_avx.h
@@ -1,6 +1,6 @@
 #ifndef __FREQ_AVX__
 #define __FREQ_AVX__
 
-void* compute_avx();
+void* compute_avx(void);
 
 #endif
diff --git a/src/x86/freq/freq_avx512.c b/src/x86/freq/freq_avx512.c
index df3ace1..e602159 100644
--- a/src/x86/freq/freq_avx512.c
+++ b/src/x86/freq/freq_avx512.c
@@ -10,7 +10,7 @@
 #include <stdint.h>
 #include "freq.h"
 
-void* compute_avx512() {
+void* compute_avx512(void) {
   bool end = false;
 
   struct timeval begin, now;
diff --git a/src/x86/freq/freq_avx512.h b/src/x86/freq/freq_avx512.h
index 53aefb3..388c19c 100644
--- a/src/x86/freq/freq_avx512.h
+++ b/src/x86/freq/freq_avx512.h
@@ -1,6 +1,6 @@
 #ifndef __FREQ_AVX512__
 #define __FREQ_AVX512__
 
-void* compute_avx512();
+void* compute_avx512(void);
 
 #endif
diff --git a/src/x86/freq/freq_nov.c b/src/x86/freq/freq_nov.c
index b351713..4fd09a7 100644
--- a/src/x86/freq/freq_nov.c
+++ b/src/x86/freq/freq_nov.c
@@ -10,7 +10,7 @@
 #include <stdint.h>
 #include "freq.h"
 
-void* compute_nov() {
+void* compute_nov(void) {
   bool end = false;
 
   struct timeval begin, now;
diff --git a/src/x86/freq/freq_nov.h b/src/x86/freq/freq_nov.h
index 1073e6c..304b800 100644
--- a/src/x86/freq/freq_nov.h
+++ b/src/x86/freq/freq_nov.h
@@ -1,6 +1,6 @@
 #ifndef __FREQ_NO_VECTOR__
 #define __FREQ_NO_VECTOR__
 
-void* compute_nov();
+void* compute_nov(void);
 
 #endif