diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index ddeac8444c873385e6dfe8ba565c674ebe569a77..e1d1a28dcab9763be645dc74e72a859fab0ae392 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -88,14 +88,14 @@ just in case, it'd be a good idea to map inputs to variables.
 #include "string.h"
 #include "stdio.h"
 
-int main() {
-	// Don't do this
-	printf("%d\n", strcspn("Hello", "Hi"));
-
-	// Do this
-	char *first = "Hello";
-	char *second = "Hi";
-	printf("%d\n", strcspn(first, second));
+int main(void) {
+    // Don't do this
+    printf("%d\n", strcspn("Hello", "Hi"));
+
+    // Do this
+    char *first = "Hello";
+    char *second = "Hi";
+    printf("%d\n", strcspn(first, second));
 }
 ```
 
@@ -120,4 +120,4 @@ You can test against verified correct output with `make verify` in the tests
 directory. You will need to manually create the correct output and put it in the
 tests/expected directory. Running any `make` commands in the tests directory
 will ***not*** rebuild relibc, so you'll need to go back to the root directory
-if you need to rebuild relibc.
\ No newline at end of file
+if you need to rebuild relibc.
diff --git a/tests/alloca.c b/tests/alloca.c
index 990bd49b356a3ba7e135556b0673e56c0183b5ff..3d774c5fccae729e8d7ba258ac25c483382e77d0 100644
--- a/tests/alloca.c
+++ b/tests/alloca.c
@@ -2,7 +2,7 @@
 #include <stdio.h>
 #include <string.h>
 
-int main(int argc, char ** argv) {
+int main(void) {
     char *str = (char *) alloca(17);
 
     memset(str, 'A', 16);
diff --git a/tests/args.c b/tests/args.c
index fd9c779701a1820d4e1484a3f42f1eb20e3cde48..e05509c40518fbe65a053941d1edb00056cbcd66 100644
--- a/tests/args.c
+++ b/tests/args.c
@@ -1,7 +1,7 @@
 #include <string.h>
 #include <unistd.h>
 
-int main(int argc, char ** argv) {
+int main(int argc, char *argv[]) {
     int i;
     for(i = 0; i < argc; i++) {
         write(STDOUT_FILENO, argv[i], strlen(argv[i]));
diff --git a/tests/arpainet.c b/tests/arpainet.c
index c93f3933c223d21fed89e58858e2bf1a1efbc7b2..cae9921b5490f8025dd8bb4a4af178615138ac0f 100644
--- a/tests/arpainet.c
+++ b/tests/arpainet.c
@@ -3,7 +3,7 @@
 #include <string.h>
 #include <stdlib.h>
 
-int main(int argc, char** argv) {
+int main(void) {
     uint32_t hl = 0xBADFACED;
     uint32_t nl = htonl(hl);
     assert(nl == 0xEDACDFBA);
diff --git a/tests/assert.c b/tests/assert.c
index 7f98bbe9c578705b5e79f799121253ad9b6b8765..0ab46cafa2d41ecf512ec216c35e5f040b30e881 100644
--- a/tests/assert.c
+++ b/tests/assert.c
@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 
-int main() {
+int main(void) {
     assert(1 == 1);
     assert(1 + 1 == 2);
     puts("yay!");
diff --git a/tests/constructor.c b/tests/constructor.c
index 01f4f9ca33bdb2c50cfb23de7740148f28169f5b..38fc58cbaf9fd037751e3cf122939e07636272c4 100644
--- a/tests/constructor.c
+++ b/tests/constructor.c
@@ -16,6 +16,6 @@ TEST(102)
 TEST(103)
 TEST(104)
 
-int main(int argc, char *argv[]) {
+int main(void) {
     puts("main");
 }
diff --git a/tests/ctype.c b/tests/ctype.c
index 46682640b51f161a0e27a8533fe24edbf53fcbb0..40ba65ae47983460428bddee25f909238bd5d590 100644
--- a/tests/ctype.c
+++ b/tests/ctype.c
@@ -293,7 +293,7 @@ size_t num_test_cases = sizeof(test_cases) / sizeof(struct test_case);
         printf("Unexpected result: " #fn "('%c') != %d // Char value: %d\n", tc.c, tc.fn, tc.c); \
     }
 
-int main(int argc, char* argv[]) {
+int main(void) {
     int retval = 0;
 
     for(int i = 0; i < num_test_cases; ++i) {
diff --git a/tests/destructor.c b/tests/destructor.c
index 57b87ff11b39867aa7e2891dfb26b49e30baa34b..40840ccde6ea8eb69bdf9b728a75018c3d9efa05 100644
--- a/tests/destructor.c
+++ b/tests/destructor.c
@@ -16,6 +16,6 @@ TEST(102)
 TEST(103)
 TEST(104)
 
-int main(int argc, char *argv[]) {
+int main(void) {
     puts("main");
 }
diff --git a/tests/dirent/main.c b/tests/dirent/main.c
index 08cea692963659615812aa8df53211ceb69c3122..430626af706ac9650037390d1d3796179564d4a5 100644
--- a/tests/dirent/main.c
+++ b/tests/dirent/main.c
@@ -2,7 +2,7 @@
 #include <errno.h>
 #include <stdio.h>
 
-int main() {
+int main(void) {
     printf("%lu\n", sizeof(struct dirent));
 
     DIR* dir = opendir("example_dir/");
diff --git a/tests/dirent/scandir.c b/tests/dirent/scandir.c
index 383a6ca0b139781742184df2e0cefc592834f4b8..2b2ea03c2b338fc271cc31aa163a9dff72dba96c 100644
--- a/tests/dirent/scandir.c
+++ b/tests/dirent/scandir.c
@@ -7,7 +7,7 @@ int filter(const struct dirent* dirent) {
     return strstr(dirent->d_name, "3") == NULL;
 }
 
-int main() {
+int main(void) {
     struct dirent** array;
     int len = scandir("example_dir/", &array, filter, alphasort);
     if (len < 0) {
diff --git a/tests/error.c b/tests/error.c
index 0b539992d475fb9b66d151c8c7ab60bd2b876f57..ac84c343b8cb517d605bf41fd4c9d4c2cabb8fbd 100644
--- a/tests/error.c
+++ b/tests/error.c
@@ -3,7 +3,7 @@
 #include <string.h>
 #include <errno.h>
 
-int main(int argc, char** argv) {
+int main(void) {
     chdir("nonexistent");
     printf("errno: %d = %s\n", errno, strerror(errno));
     perror("perror");
diff --git a/tests/fcntl/create.c b/tests/fcntl/create.c
index 864496830b35d8bfffd587514c34cdbafd6d55e0..8e70cb6c608aff57f68c299cab6c67115bd9798b 100644
--- a/tests/fcntl/create.c
+++ b/tests/fcntl/create.c
@@ -1,7 +1,7 @@
 #include <fcntl.h>
 #include <unistd.h>
 
-int main(int argc, char ** argv) {
+int main(void) {
     int fd = creat("create.out", 0755);
     if (fd >= 0) {
         write(fd, "Hello World!\n", 13);
diff --git a/tests/fcntl/fcntl.c b/tests/fcntl/fcntl.c
index 4ce261d18828fcb85c3bb3d5cfcbbc9fe7ef5222..474e163f563e302b250a4f9887269b3c5c83a35d 100644
--- a/tests/fcntl/fcntl.c
+++ b/tests/fcntl/fcntl.c
@@ -2,7 +2,7 @@
 #include <stdio.h>
 #include <unistd.h>
 
-int main() {
+int main(void) {
     //Lose our fd and pull it again
     creat("fcntl.out", 0777);
     int newfd = open("fcntl.out", 0);
diff --git a/tests/fnmatch.c b/tests/fnmatch.c
index 4d10a642ef6318ff17ae6ec8e1897047cbba696e..9fa673f539f1ec14fa0bb692fadd6509c082599f 100644
--- a/tests/fnmatch.c
+++ b/tests/fnmatch.c
@@ -9,7 +9,7 @@ void test(char* pattern, char* input, int flags) {
     }
 }
 
-int main() {
+int main(void) {
     puts("Should succeed:");
     test("*World", "Hello World", 0);
     test("*World", "World", 0);
diff --git a/tests/libgen.c b/tests/libgen.c
index f38f70f0f01cdd36025482ca61169e1e5d1989c3..fd79f5b9d6438e917768c275514a8ed3b056e4ff 100644
--- a/tests/libgen.c
+++ b/tests/libgen.c
@@ -18,7 +18,7 @@ char * get_mutable_string(char *str) {
   return copy;
 }
 
-void test_basename() {
+void test_basename(void) {
   test_case test_cases[] =
   { {"/usr/lib", "lib"},
     {"//usr//lib//", "lib"},
@@ -44,7 +44,7 @@ void test_basename() {
   return;
 }
 
-void test_dirname() {
+void test_dirname(void) {
   test_case test_cases[] =
   { {"/usr/lib", "/usr"},
     {"//usr//lib//", "//usr"},
@@ -73,7 +73,7 @@ void test_dirname() {
   return;
 }
 
-int main() {
+int main(void) {
   printf("Testing libgen.h\n");
   test_basename();
   test_dirname();
diff --git a/tests/locale.c b/tests/locale.c
index 9358bc5554319b7dbfdc3ef62bfdb90a519c008f..dde3364da4728c1aff54691a694f9f718e8befce 100644
--- a/tests/locale.c
+++ b/tests/locale.c
@@ -2,7 +2,7 @@
 #include <stdio.h>
 #include <string.h>
 
-int main() {
+int main(void) {
     // TODO: Implement locale properly and test it here
     char* val = setlocale(LC_ALL, NULL);
     if (strcmp(val, "C") == 0) {
diff --git a/tests/math.c b/tests/math.c
index fb53fa2438dbff7a1e3b392b9ff8bda42928fe75..014529f468315d55c38df71fd0e6802d45012505 100644
--- a/tests/math.c
+++ b/tests/math.c
@@ -1,7 +1,7 @@
 #include <math.h>
 #include <stdio.h>
 
-int main(int argc, char ** argv) {
+int main(void) {
     double pi = 3.14;
     float c = cos(pi);
     printf("cos(%f) = %f\n", pi, c);
diff --git a/tests/netdb/netdb.c b/tests/netdb/netdb.c
index 9bbbf3e2834ef7964c4611aa2538b5a2f670e9e1..d81f08d632a0c76b0d6c10fc2039946f34c74992 100644
--- a/tests/netdb/netdb.c
+++ b/tests/netdb/netdb.c
@@ -225,6 +225,6 @@ do_test (void)
   return (error_count != 0);
 }
 
-int main() {
+int main(void) {
     do_test();
 }
diff --git a/tests/pwd.c b/tests/pwd.c
index 52b3511675dab441f07c9aa605c5161b885a0f4b..77087425efdf1c497a7ba4feb373a552a15d890b 100644
--- a/tests/pwd.c
+++ b/tests/pwd.c
@@ -13,7 +13,7 @@ void print(struct passwd *pwd) {
     printf("pw_shell: %s\n", pwd->pw_shell);
 }
 
-int main() {
+int main(void) {
     puts("--- Checking getpwuid ---");
     errno = 0;
     struct passwd *pwd = getpwuid(0);
diff --git a/tests/regex.c b/tests/regex.c
index cd692f89b31660fc9000078a4d75bdb29f476f28..b74a0f2ce69894e103bcf1841f7e2dffb2d23333 100644
--- a/tests/regex.c
+++ b/tests/regex.c
@@ -1,7 +1,7 @@
 #include <regex.h>
 #include <stdio.h>
 
-int main() {
+int main(void) {
     regex_t regex;
     char error_buf[256];
 
diff --git a/tests/resource/getrusage.c b/tests/resource/getrusage.c
index a844335032c1622aba3abe03e24143645b83a7d0..e04a623910bac07c7d55fc6d33ddc9c890aebe2c 100644
--- a/tests/resource/getrusage.c
+++ b/tests/resource/getrusage.c
@@ -6,7 +6,7 @@ void ptimeval(struct timeval* val) {
     printf("{ tv_sec: %ld, tv_usec: %ld }\n", val->tv_sec, val->tv_usec);
 }
 
-int main() {
+int main(void) {
     struct rusage r_usage;
     if (getrusage(RUSAGE_SELF, &r_usage) < 0) {
         perror("getrusage");
diff --git a/tests/select.c b/tests/select.c
index ba053a1e09b1bc522953c34d620c00677157b250..596a589a832615b34101840c5fbb13b31301d686 100644
--- a/tests/select.c
+++ b/tests/select.c
@@ -3,7 +3,7 @@
 #include <sys/select.h>
 #include <unistd.h>
 
-int main() {
+int main(void) {
     int fd = open("select.c", 0, 0);
 
     fd_set read;
diff --git a/tests/setjmp.c b/tests/setjmp.c
index c45390bf4a21241007069f8b1f260ccc05851647..fe117e4dec9d75c14821399b46132569e6d1bfe3 100644
--- a/tests/setjmp.c
+++ b/tests/setjmp.c
@@ -1,7 +1,7 @@
 #include <stdio.h>
 #include <setjmp.h>
 
-int main() {
+int main(void) {
     jmp_buf buf;
     if (setjmp(buf)) {
         puts("hi from jump");
diff --git a/tests/signal.c b/tests/signal.c
index 7f41785613ea33d76d217a86b7be639e0906c41d..aa9a563e01a48924bc70b388eb8fb62e8d35c9a2 100644
--- a/tests/signal.c
+++ b/tests/signal.c
@@ -7,7 +7,7 @@ void handler(int sig) {
     puts("Signal handler called!");
 }
 
-int main() {
+int main(void) {
     if (signal(SIGUSR1, &handler) == SIG_ERR) {
         puts("Signal error!");
         printf("%d\n", errno);
diff --git a/tests/stdio/all.c b/tests/stdio/all.c
index 118f46541c89b0e461b67978547d6ddfca7e67df..c049e3eb0e8911e8dfb2c1115bd00ad505ce1b1a 100644
--- a/tests/stdio/all.c
+++ b/tests/stdio/all.c
@@ -1,7 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-int main(int argc, char ** argv) {
+int main(void) {
 	FILE *f = fopen("stdio/stdio.in", "r");
 	printf("%c\n", fgetc(f));
 	ungetc('H', f);
diff --git a/tests/stdio/buffer.c b/tests/stdio/buffer.c
index c5d55944bfa9950bfef15ddd92c4d43a2306e1d1..50b236f14829ca9df62b969a5a336a9d06b55433 100644
--- a/tests/stdio/buffer.c
+++ b/tests/stdio/buffer.c
@@ -1,6 +1,6 @@
 #include <stdio.h>
 
-int main() {
+int main(void) {
     // Tests what used to be a bug with buffering
     fwrite("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", 1, 999, stdout);
     fwrite("Test\n", 1, 5, stdout);
diff --git a/tests/stdio/fgets.c b/tests/stdio/fgets.c
index c89e491ae04acce7cf0ba19601ea1d71140901d3..404002a8b2c3c4fe9d6f68ff19f713840fad304d 100644
--- a/tests/stdio/fgets.c
+++ b/tests/stdio/fgets.c
@@ -1,6 +1,6 @@
 #include <stdio.h>
 
-int main() {
+int main(void) {
     //FILE *f = fopen("/etc/ssl/certs/ca-certificates.crt", "r");
     FILE *f = fopen("stdio/stdio.in", "r");
     char line[256];
diff --git a/tests/stdio/fputs.c b/tests/stdio/fputs.c
index 34ac5f361a99f638811112c4616c146431783fe6..2ce599203c685ab0b76aed48cd0a517778d8147c 100644
--- a/tests/stdio/fputs.c
+++ b/tests/stdio/fputs.c
@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <errno.h>
 
-int main(int argc, char ** argv) {
+int main(void) {
 	FILE *f = fopen("stdio/fputs.out", "w");
 	char *in = "Hello World!";
 	fputs(in, f); // calls fwrite, helpers::fwritex, internal::to_write and internal::stdio_write
diff --git a/tests/stdio/fread.c b/tests/stdio/fread.c
index 40b6f69e579b0ac406e80a5c438c53544dbf8be4..f87e9172b164c24d1c1785645352430962d38fd7 100644
--- a/tests/stdio/fread.c
+++ b/tests/stdio/fread.c
@@ -1,7 +1,7 @@
 #include <errno.h>
 #include <stdio.h>
 
-int main(int argc, char *argv[]) {
+int main(void) {
     FILE *fp = fopen("stdio/fread.in", "rb");
 
     char buf[33] = { 0 };
diff --git a/tests/stdio/freopen.c b/tests/stdio/freopen.c
index 7bf3b64f20c3fcdfe351b9465c60eae7692d9a9a..3189b7e64d256c6b773ebc898d4a8310137c5fd9 100644
--- a/tests/stdio/freopen.c
+++ b/tests/stdio/freopen.c
@@ -1,6 +1,6 @@
 #include <stdio.h>
 
-int main(int argc, char ** argv) {
+int main(void) {
 	freopen("stdio/stdio.in", "r", stdin);
 	char in[6];
 	fgets(in, 6, stdin);
diff --git a/tests/stdio/fseek.c b/tests/stdio/fseek.c
index 84f544d2a2dee968051600c52cd7c2ca216119b5..eed59eca0c1632949cbe08101328e844dce2cd66 100644
--- a/tests/stdio/fseek.c
+++ b/tests/stdio/fseek.c
@@ -1,6 +1,6 @@
 #include <stdio.h>
 
-int main() {
+int main(void) {
 	FILE *f = fopen("stdio/stdio.in", "r");
     if (fseek(f, 14, SEEK_CUR) < 0) {
         puts("fseek error");
diff --git a/tests/stdio/fwrite.c b/tests/stdio/fwrite.c
index 85da119054336ac7a21ec858b900980c6b67e19c..37df8a75c91da1aaf9fae9822c23c6575c738aae 100644
--- a/tests/stdio/fwrite.c
+++ b/tests/stdio/fwrite.c
@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <errno.h>
 
-int main(int argc, char ** argv) {
+int main(void) {
 	FILE *f = fopen("stdio/fwrite.out", "w");
 	const char ptr[] = "Hello World!";
 
diff --git a/tests/stdio/getc_unget.c b/tests/stdio/getc_unget.c
index f8008534fb0c4718f961e58c3c4a9f2dd50539a8..257170a04b522521f665409795c028e95a768906 100644
--- a/tests/stdio/getc_unget.c
+++ b/tests/stdio/getc_unget.c
@@ -1,6 +1,6 @@
 #include <stdio.h>
 
-int main(int argc, char ** argv) {
+int main(void) {
 	ungetc('h', stdin);
 	char c;
 	if ((c = getchar()) == 'h') {
diff --git a/tests/stdio/mutex.c b/tests/stdio/mutex.c
index 032ced27e9151f996e50bc6c02d3be92197f2fc9..04f7b386c9c59be66e0b59cf5b2281e39f96b5f3 100644
--- a/tests/stdio/mutex.c
+++ b/tests/stdio/mutex.c
@@ -1,6 +1,6 @@
 #include <stdio.h>
 
-int main() {
+int main(void) {
     FILE* f = fopen("stdio/stdio.in", "r");
 
     flockfile(f);
diff --git a/tests/stdio/popen.c b/tests/stdio/popen.c
index 9550b0ef24b5e2dbcd9d2bf41328d261ac3f939f..364b3753b5b9e332630e9f9b571c83ca48ccfc37 100644
--- a/tests/stdio/popen.c
+++ b/tests/stdio/popen.c
@@ -1,6 +1,6 @@
 #include <stdio.h>
 
-int main(int argc, char **argv) {
+int main(void) {
     FILE *fp;
     int status;
     char path[256];
diff --git a/tests/stdio/printf.c b/tests/stdio/printf.c
index 3ef0c9b224caa22ab7a491adb21b079557b25ce8..833b39c84cf4fe2d0869d02e7b11bee7570e389a 100644
--- a/tests/stdio/printf.c
+++ b/tests/stdio/printf.c
@@ -1,6 +1,6 @@
 #include <stdio.h>
 
-int main(int argc, char ** argv) {
+int main(void) {
     int sofar = 0;
     int len = printf(
         "percent: %%\nstring: %s\nchar: %c\nchar: %c\nint: %d\n%nuint: %u\nhex: %x\nHEX: %X\nstring: %s\n",
diff --git a/tests/stdio/rename.c b/tests/stdio/rename.c
index 189ba227712dd49b467503d571c7c821ffa91529..537b2dc6a46dd9f21a1602b80abb39e398ea0a67 100644
--- a/tests/stdio/rename.c
+++ b/tests/stdio/rename.c
@@ -8,7 +8,7 @@ static char newpath[] = "new-name.out";
 static char str[] = "Hello, World!";
 int str_len = 13;
 
-int main() {
+int main(void) {
     char buf[14];
     buf[13] = 0x00;
     int fd = creat(oldpath, 0777);
diff --git a/tests/stdio/scanf.c b/tests/stdio/scanf.c
index 3f6a23663197855ba134769e6d5cada09d7172af..a19daaf3bb35f9c12b60bb16fe5f4ae31fc7ebe8 100644
--- a/tests/stdio/scanf.c
+++ b/tests/stdio/scanf.c
@@ -25,7 +25,7 @@ void test(char* fmt_in, char* input, struct params *p, ...) {
     );
 }
 
-int main(int argc, char ** argv) {
+int main(void) {
     struct params p = { .c = 'a' };
 
     test("%hhd %d", "12 345", &p, &p.sa, &p.ia);
diff --git a/tests/stdio/setvbuf.c b/tests/stdio/setvbuf.c
index 62a13aeeb59b05c2bec4a0f4598a5633a64b69c7..46191f53cd35385967ecd685fdb03a89aba0af58 100644
--- a/tests/stdio/setvbuf.c
+++ b/tests/stdio/setvbuf.c
@@ -1,7 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-int main(int argc, char ** argv) {
+int main(void) {
 	setvbuf(stdout, 0, _IONBF, 0);
 	FILE *f = fopen("stdio/stdio.in", "r");
 	setvbuf(f, 0, _IONBF, 0);
diff --git a/tests/stdio/sprintf.c b/tests/stdio/sprintf.c
index 7e42245bc22ef12374d6729ffa1f1570ad4f46f7..3205473e3babeede22dc6aec4382688a02b25c21 100644
--- a/tests/stdio/sprintf.c
+++ b/tests/stdio/sprintf.c
@@ -1,7 +1,7 @@
 #include <stdio.h>
 #include <string.h>
 
-int main(int argc, char ** argv) {
+int main(void) {
     char buffer[72];
 
     int ret = sprintf(
diff --git a/tests/stdlib/a64l.c b/tests/stdlib/a64l.c
index 8036d9e3fb0c85391effadde4986a17fc66d8bbc..14d44a9f83aaa9377894b662c1ec98c04da94f47 100644
--- a/tests/stdlib/a64l.c
+++ b/tests/stdlib/a64l.c
@@ -1,7 +1,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 
-int main(int argc, char* argv[]) {
+int main(void) {
     char * s = "azAZ9."; // test boundaries
     long l = a64l(s);
     if (l != 194301926) {
diff --git a/tests/stdlib/alloc.c b/tests/stdlib/alloc.c
index bfb8673400f0b4b350f3e341f7345c36ec78798d..85d6c9c07656d33ad00e46db276328c3b1a90af0 100644
--- a/tests/stdlib/alloc.c
+++ b/tests/stdlib/alloc.c
@@ -2,7 +2,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-int main(int argc, char ** argv) {
+int main(void) {
     char * ptr = (char *)malloc(256);
     printf("malloc %p\n", ptr);
     int i;
diff --git a/tests/stdlib/atof.c b/tests/stdlib/atof.c
index 1bfb9d0e220d4029fadb86716017705061958146..37f8d11299bd20144330dea1300154120223d24e 100644
--- a/tests/stdlib/atof.c
+++ b/tests/stdlib/atof.c
@@ -1,7 +1,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 
-int main(int argc, char* argv[]) {
+int main(void) {
     double d = atof("-3.14");
     printf("%f\n", d);
     return 0;
diff --git a/tests/stdlib/atoi.c b/tests/stdlib/atoi.c
index e9af8da95e646e7bfdc244503bd1bced71a4d3ff..8ce33962f0b8506c7af10888d60c405a5d57f83f 100644
--- a/tests/stdlib/atoi.c
+++ b/tests/stdlib/atoi.c
@@ -1,7 +1,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 
-int main(int argc, char* argv[]) {
+int main(void) {
     printf("%d\n", atoi("         -42"));
     printf("%d\n", atoi(" +555"));
     printf("%d\n", atoi("   1234567890    "));
diff --git a/tests/stdlib/bsearch.c b/tests/stdlib/bsearch.c
index c8e43c612bf4e00d1183be261b17e19666637f3b..9ccd1a7d4700dffe58129c06ca2d4899d59befeb 100644
--- a/tests/stdlib/bsearch.c
+++ b/tests/stdlib/bsearch.c
@@ -19,7 +19,7 @@ int int_cmp(const void* a, const void* b) {
 
 
 
-int main(int argc, char* argv[]) {
+int main(void) {
   int x = 0;
   int y = 1024;
 
diff --git a/tests/stdlib/div.c b/tests/stdlib/div.c
index 22acb9176a78cf80227188bffd16836f9d729ea2..7752fb5d177be7433a483f3632538e100ace1e75 100644
--- a/tests/stdlib/div.c
+++ b/tests/stdlib/div.c
@@ -3,10 +3,9 @@
          volatile long double ld;
          volatile unsigned long long ll;
          lldiv_t mydivt;
-int
-main ()
-{
-char* tmp;
+
+int main(void) {
+         char* tmp;
          f = strtof("gnu", &tmp);
          ld = strtold("gnu", &tmp);
          ll = strtoll("gnu", &tmp, 10);
diff --git a/tests/stdlib/env.c b/tests/stdlib/env.c
index e0a821c839892d27d54f31f666a7f861621ea769..684e78bedf4abf757f951eaf32b0935b2c1d624f 100644
--- a/tests/stdlib/env.c
+++ b/tests/stdlib/env.c
@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-int main() {
+int main(void) {
     //puts(getenv("SHELL"));
     //puts(getenv("CC"));
 
diff --git a/tests/stdlib/mkostemps.c b/tests/stdlib/mkostemps.c
index 2ada5d1f48a6732b3bc689bf6251d1cf4ef3ab86..c3547f49c20e269dda5850f62c95df1c7e739d5e 100644
--- a/tests/stdlib/mkostemps.c
+++ b/tests/stdlib/mkostemps.c
@@ -2,7 +2,7 @@
 #include <stdio.h>
 #include <string.h>
 
-int main(int argc, char** argv) {
+int main(void) {
     char* file_name = (char*) calloc(18, sizeof(char));
     strcpy(file_name, "tempXXXXXX.suffix");
     int fd = mkostemps(file_name, 7, 0);
diff --git a/tests/stdlib/mktemp.c b/tests/stdlib/mktemp.c
index eaafe83480e2d54ebf0dd95b15c1b8c646fceb3d..e2394f63603181f0b4696fdb53e7726204bebe73 100644
--- a/tests/stdlib/mktemp.c
+++ b/tests/stdlib/mktemp.c
@@ -2,7 +2,7 @@
 #include <stdio.h>
 #include <string.h>
 
-int main(int argc, char** argv) {
+int main(void) {
     char* string = (char*) calloc(20, sizeof(char));
     strcpy(string, "tempXXXXXX");
     mktemp(string);
diff --git a/tests/stdlib/rand.c b/tests/stdlib/rand.c
index 484b09906b4d3555280ef0a1b7b92fc41fb0b3a8..f3883c3fdbdc9246cc422257c78a2831d340b330 100644
--- a/tests/stdlib/rand.c
+++ b/tests/stdlib/rand.c
@@ -1,7 +1,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(void) {
     printf("%d\n", rand());
     srand(259);
     printf("%d\n", rand());
diff --git a/tests/stdlib/realpath.c b/tests/stdlib/realpath.c
index c6a679a4d508c28661492032ae33dfd94aa95bbd..918874ee2366a118cb6d2b3ae713971d9eee7b1f 100644
--- a/tests/stdlib/realpath.c
+++ b/tests/stdlib/realpath.c
@@ -4,7 +4,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-int main() {
+int main(void) {
     char* path = realpath("stdlib/realpath.c", NULL);
     if (!path) {
         perror("realpath");
diff --git a/tests/stdlib/strtod.c b/tests/stdlib/strtod.c
index 21a728050d30ed9fa99c4ddbdfe664c08f0e1689..ae88af4db2648110d2d3585454752511cfdcd817 100644
--- a/tests/stdlib/strtod.c
+++ b/tests/stdlib/strtod.c
@@ -1,7 +1,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 
-int main() {
+int main(void) {
     char* endptr = 0;
     double d;
 
diff --git a/tests/stdlib/strtol.c b/tests/stdlib/strtol.c
index c088e144b9bbd49a011982a8c90c7be31a3d2ada..e98964ad5968d0bc9b7f298a9abcb24f6c02f31d 100644
--- a/tests/stdlib/strtol.c
+++ b/tests/stdlib/strtol.c
@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 
-int main(int argc, char* argv[]) {
+int main(void) {
     printf("%ld\n", strtol("         -42", NULL, 0));
     printf("%ld\n", strtol(" +555", NULL, 0));
     printf("%ld\n", strtol("   1234567890    ", NULL, 0));
diff --git a/tests/stdlib/strtoul.c b/tests/stdlib/strtoul.c
index 4431a720d231ef735c1b0d07d3264be4c9f38714..2e7f3686730b770a0bc10c5a69a461d44251b010 100644
--- a/tests/stdlib/strtoul.c
+++ b/tests/stdlib/strtoul.c
@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 
-int main(int argc, char* argv[]) {
+int main(void) {
     printf("%ld\n", strtoul("         -42", NULL, 0));
     printf("%ld\n", strtoul(" +555", NULL, 0));
     printf("%ld\n", strtoul("   1234567890    ", NULL, 0));
diff --git a/tests/stdlib/system.c b/tests/stdlib/system.c
index 8c4cda187c5cf8f0c266358c9444e95764c2d37c..9acc8d6b3340f3a88837d3cb674682815091850a 100644
--- a/tests/stdlib/system.c
+++ b/tests/stdlib/system.c
@@ -1,6 +1,6 @@
 #include <stdlib.h>
 
-int main(int argc, char ** argv) {
+int main(void) {
     system("echo test of system");
     return 0;
 }
diff --git a/tests/string/mem.c b/tests/string/mem.c
index 121a8f5f3b93c29e2cab705ac246df04251147ff..43424b81651134ff17c07977584006085ea1bb17 100644
--- a/tests/string/mem.c
+++ b/tests/string/mem.c
@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-int main(int argc, char ** argv) {
+int main(void) {
     puts("# mem #");
     char arr[100];
     memset(arr, 0, 100); // Compiler builtin, should work
diff --git a/tests/string/strcat.c b/tests/string/strcat.c
index 6913c55757f738faec1b952549ce925f0826e639..2ccc932729e8bededd3a20ac0ad16651ab37fbf9 100644
--- a/tests/string/strcat.c
+++ b/tests/string/strcat.c
@@ -1,7 +1,7 @@
 #include <string.h>
 #include <stdio.h>
 
-int main(int argc, char* argv[]) {
+int main(void) {
     char dest1[12] = "hello";
 	  printf("%s\n", strcat(dest1, " world")); // should be hello world
 
diff --git a/tests/string/strchr.c b/tests/string/strchr.c
index 202737faac070340016b0ae714b49bcae2880588..7ef4452eef095e05713d35b22a4a70197f163026 100644
--- a/tests/string/strchr.c
+++ b/tests/string/strchr.c
@@ -1,7 +1,7 @@
 #include <string.h>
 #include <stdio.h>
 
-int main(int argc, char* argv[]) {
+int main(void) {
 	printf("%s\n", strchr("hello", 'e')); // should be ello
 	printf("%s\n", strchr("world", 'l')); // should be ld
 	printf("%i\n", strchr("world", 0) == NULL); // should be 1
diff --git a/tests/string/strcpy.c b/tests/string/strcpy.c
index f0c7d792590ccd67b2a6057e8c009715f3429e09..69159d738e275b70686160084fa759ad272401f4 100644
--- a/tests/string/strcpy.c
+++ b/tests/string/strcpy.c
@@ -1,7 +1,7 @@
 #include <stdio.h>
 #include <string.h>
 
-int main() {
+int main(void) {
     char dst[20];
 
     strcpy(dst, "strcpy works!");
diff --git a/tests/string/strcspn.c b/tests/string/strcspn.c
index 859d88043521ec58cf4cc72f0866012e6e048221..b9a81c8b28c86d30d78b8edcc8d3250b7bae7a84 100644
--- a/tests/string/strcspn.c
+++ b/tests/string/strcspn.c
@@ -1,7 +1,7 @@
 #include <string.h>
 #include <stdio.h>
 
-int main(int argc, char* argv[]) {
+int main(void) {
 	char *world = "world";
 	printf("%ld\n", strcspn("hello", world)); // should be 2
 	printf("%ld\n", strcspn("banana", world)); // should be 6
diff --git a/tests/string/strncmp.c b/tests/string/strncmp.c
index efb2bea9783af619a6bdf1995ab3b4feaff6b813..122a1ca64765861d451859942e24bf65a7ae768f 100644
--- a/tests/string/strncmp.c
+++ b/tests/string/strncmp.c
@@ -1,7 +1,7 @@
 #include <string.h>
 #include <stdio.h>
 
-int main(int argc, char* argv[]) {
+int main(void) {
     printf("%d\n", strncmp("a", "aa", 2));
     printf("%d\n", strncmp("a", "aä", 2));
     printf("%d\n", strncmp("\xFF", "\xFE", 2));
diff --git a/tests/string/strpbrk.c b/tests/string/strpbrk.c
index dc0ebf7c534c1a92ea997a7aa212f8227c2cfc5d..248ade939318e3eded8e855532c10455daa0531d 100644
--- a/tests/string/strpbrk.c
+++ b/tests/string/strpbrk.c
@@ -1,7 +1,7 @@
 #include <string.h>
 #include <stdio.h>
 
-int main(int argc, char* argv[]) {
+int main(void) {
     char* source = "The quick drawn fix jumps over the lazy bug";
 
     // should be "The quick drawn fix jumps over the lazy bug"
diff --git a/tests/string/strrchr.c b/tests/string/strrchr.c
index 7edc98040b36fb4cdafd327384c9d840a74c0ee3..d999cacc4271b1df0ce4254cab834419bd6f0ab0 100644
--- a/tests/string/strrchr.c
+++ b/tests/string/strrchr.c
@@ -1,8 +1,7 @@
 #include <string.h>
 #include <stdio.h>
 
-
-int main(int argc, char* argv[]) {
+int main(void) {
   char s0[] = "hello, world";
   char* ptr = strrchr(s0, 'l');
   if (ptr != &s0[10]) {
diff --git a/tests/string/strspn.c b/tests/string/strspn.c
index 52431a70ff8d3bb3c35385c4c3360534f58b4162..30caaaaf97bb93782e49d58e1baec23374e5be7c 100644
--- a/tests/string/strspn.c
+++ b/tests/string/strspn.c
@@ -1,7 +1,7 @@
 #include <string.h>
 #include <stdio.h>
 
-int main(int argc, char* argv[]) {
+int main(void) {
 	char *hello = "hello";
 	char *world = "world";
 	char *banana = "banana";
diff --git a/tests/string/strstr.c b/tests/string/strstr.c
index cc23f070fd365170a76548f5e02f66d7b196e7ed..90c8f349757b80e2afc943a7b83bcd772ebb3c24 100644
--- a/tests/string/strstr.c
+++ b/tests/string/strstr.c
@@ -1,7 +1,7 @@
 #include <string.h>
 #include <stdio.h>
 
-int main(int argc, char* argv[]) {
+int main(void) {
     printf("%s\n", strstr("In relibc we trust", "rust"));
     printf("%s\n", strstr("In relibc we trust", "libc"));
     printf("%s\n", strstr("In relibc we trust", "bugs"));
diff --git a/tests/string/strtok.c b/tests/string/strtok.c
index 18436d9f7ea36cc55854d8a80b3734094f9414b7..6333f5c3b814b06fa461110d1b3c392147895fd8 100644
--- a/tests/string/strtok.c
+++ b/tests/string/strtok.c
@@ -1,7 +1,7 @@
 #include <string.h>
 #include <stdio.h>
 
-int main(int argc, char* argv[]) {
+int main(void) {
     char source[] = "I'd just like to interject for a moment.  What you're referring to as Linux, "
                     "is in fact, GNU/Linux, or as I've recently taken to calling it, GNU plus Linux.\n";
 
diff --git a/tests/string/strtok_r.c b/tests/string/strtok_r.c
index 6b3f501422148aa0588e23704a01e06ee4bc5b1e..9238f0a185515291b79385c06c1e23d1ba21a6f8 100644
--- a/tests/string/strtok_r.c
+++ b/tests/string/strtok_r.c
@@ -1,7 +1,7 @@
 #include <string.h>
 #include <stdio.h>
 
-int main(int argc, char* argv[]) {
+int main(void) {
     char source[] = "I'd just like to interject for a moment.  What you're referring to as Linux, "
                     "is in fact, GNU/Linux, or as I've recently taken to calling it, GNU plus Linux.\n";
     char* sp;
diff --git a/tests/strings.c b/tests/strings.c
index fefb631a6800af459aef2dff3dd987c3e4fe25c8..11cdb48feb9fa35e82f1133dda8a57f38deeefc9 100644
--- a/tests/strings.c
+++ b/tests/strings.c
@@ -3,7 +3,7 @@
 #include <stdio.h>
 #include <strings.h>
 
-int main() {
+int main(void) {
     assert(!bcmp("hello", "hehe", 2));
     assert(bcmp("hello", "haha", 2));
 
diff --git a/tests/sys_utsname/uname.c b/tests/sys_utsname/uname.c
index 05ad034019bc004d0546cca99cefb57784e98a90..8e094df416cba07aa2d6dd83d65024004db2e4ed 100644
--- a/tests/sys_utsname/uname.c
+++ b/tests/sys_utsname/uname.c
@@ -1,7 +1,7 @@
 #include <stdio.h>
 #include <sys/utsname.h>
 
-int main() {
+int main(void) {
     struct utsname system_info;
 
     int result = uname(&system_info);
diff --git a/tests/time/asctime.c b/tests/time/asctime.c
index a2a3db03ff36eafe60c64af90d54409463d1f498..a76b032b23327cb959c95b129afaccb85d79a0ef 100644
--- a/tests/time/asctime.c
+++ b/tests/time/asctime.c
@@ -3,7 +3,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-int main(int argc, char** argv) {
+int main(void) {
     time_t a = 0;
     struct tm *time_info = gmtime(&a);
 
diff --git a/tests/time/gettimeofday.c b/tests/time/gettimeofday.c
index 7cd71d9aeeac569c3fc8e483d69ff88ca82ec347..a17e2aedf553ca5a10b8037254cead3b254580db 100644
--- a/tests/time/gettimeofday.c
+++ b/tests/time/gettimeofday.c
@@ -1,7 +1,7 @@
 #include <sys/time.h>
 #include <stdio.h>
 
-int main() {
+int main(void) {
     struct timeval tv;
     gettimeofday(&tv, NULL);
     printf("%ld: %ld\n", tv.tv_sec, tv.tv_usec);
diff --git a/tests/time/gmtime.c b/tests/time/gmtime.c
index 836822db350a171b0166f9f02663e41cf9001690..f8be76adcecbc4a0b174ac9345ecbe9bc6a21ac5 100644
--- a/tests/time/gmtime.c
+++ b/tests/time/gmtime.c
@@ -3,7 +3,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-int main(int argc, char** argv) {
+int main(void) {
     time_t a = 0;
     struct tm expected = { .tm_sec = 0, .tm_min = 0, .tm_hour = 0, .tm_mday = 1, .tm_year = 70,
                     .tm_wday = 4, .tm_yday = 0, .tm_isdst = 0, .tm_gmtoff = 0, .tm_zone = "UTC" };
diff --git a/tests/time/localtime.c b/tests/time/localtime.c
index 3792531b95e6f6b3c48388c393bafab18e95f82c..5f96b3ea2302720ef2c085b1295add987ad12341 100644
--- a/tests/time/localtime.c
+++ b/tests/time/localtime.c
@@ -1,7 +1,7 @@
 #include <stdio.h>
 #include <time.h>
 
-int main() {
+int main(void) {
     int day = 60 * 60 * 24;
     time_t inputs[] = { -(day * 33), -day, -1, -500, 0, 1, 1531454950 };
     for (int i = 0; i < (sizeof(inputs) / sizeof(time_t)); i += 1) {
diff --git a/tests/time/macros.c b/tests/time/macros.c
index b33f78b7505238e58f1a067ae64a2b54fb0affbd..737dab831f0b39dd2e7ccfb76da4a2d6e36ad7d0 100644
--- a/tests/time/macros.c
+++ b/tests/time/macros.c
@@ -1,7 +1,7 @@
 #include <assert.h>
 #include <sys/time.h>
 
-int main() {
+int main(void) {
     struct timeval x = { .tv_usec = 15 };
     struct timeval y = { 0 };
     struct timeval z = { 0 };
diff --git a/tests/time/mktime.c b/tests/time/mktime.c
index c99102f673ce78d75b7aeb96b8ee5e77d2dc0df9..94b96eb8c200f72b77a5fcc15129e28554ba05e1 100644
--- a/tests/time/mktime.c
+++ b/tests/time/mktime.c
@@ -18,7 +18,8 @@ int check(time_t input) {
     }
     return 0;
 }
-int main() {
+
+int main(void) {
     struct tm t = { 0 };
 
     t.tm_year = 71;
diff --git a/tests/time/strftime.c b/tests/time/strftime.c
index 56ecc6f9e2c86d186aa2a711cff8f734c1c3745a..99da578bfd92f5643a001372734a73f7f2ee8db0 100644
--- a/tests/time/strftime.c
+++ b/tests/time/strftime.c
@@ -8,7 +8,8 @@ void print(time_t timestamp, char* fmt) {
     printf("%zu: %s\n", n, out);
     free(out);
 }
-int main() {
+
+int main(void) {
     print(1531808742, "%a %A %b %B");
     print(1531808742, "The %Cst century");
     print(1531808742, "%I:%M:%S %p");
diff --git a/tests/time/time.c b/tests/time/time.c
index 3dc120b2703cd77557bdbb26f6ce8eae8329518e..3fe2fc2322aeb65b95c579998d65ade59c9072f2 100644
--- a/tests/time/time.c
+++ b/tests/time/time.c
@@ -1,7 +1,7 @@
 #include <time.h>
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(void) {
     struct timespec tm = {0, 0};
 
     int cgt = clock_gettime(CLOCK_REALTIME, &tm);
diff --git a/tests/time/times.c b/tests/time/times.c
index 975aae2dd042e55d722d36ce68d8105c46f1def4..91829b4cadb1f1c9612366b652b75dc85ad560b2 100644
--- a/tests/time/times.c
+++ b/tests/time/times.c
@@ -2,7 +2,7 @@
 #include <sys/times.h>
 #include <unistd.h>
 
-int main() {
+int main(void) {
     struct tms tms;
     printf("return: %ld\n", times(&tms));
 
diff --git a/tests/unistd/access.c b/tests/unistd/access.c
index 9491aa5f5de4648cdea9248af6ee04b34298b3f5..2ba3d0184952a476dc68693bee8acaad7bc014e4 100644
--- a/tests/unistd/access.c
+++ b/tests/unistd/access.c
@@ -1,7 +1,7 @@
 #include <stdio.h>
 #include <unistd.h>
 
-int main() {
+int main(void) {
     if (access("example_dir/1-never-gonna-give-you-up", R_OK | W_OK)) {
         perror("access");
         return 1;
diff --git a/tests/unistd/brk.c b/tests/unistd/brk.c
index 138b0080f3af8ad22df5a5f9c89223483f96c76e..60d3ad0d14c1c2e217f7fd7b43b5ff8ce52548d5 100644
--- a/tests/unistd/brk.c
+++ b/tests/unistd/brk.c
@@ -1,7 +1,7 @@
 #include <unistd.h>
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(void) {
     int status = brk((void*)100);
     printf("brk exited with status code %d\n", status);
     return 0;
diff --git a/tests/unistd/chdir.c b/tests/unistd/chdir.c
index be0e29018f734f843dc30aa9c1c119c1f7eae3cb..f0cd849af0858c5bc34c0336f8b589e885bb671f 100644
--- a/tests/unistd/chdir.c
+++ b/tests/unistd/chdir.c
@@ -2,7 +2,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-int main(int argc, char** argv) {
+int main(void) {
     char* cwd1 = malloc(4096*sizeof(char));//(char*) calloc(4096 + 1, sizeof(char));
     getcwd(cwd1, 4096);
     printf("initial cwd: %s\n", cwd1);
diff --git a/tests/unistd/dup.c b/tests/unistd/dup.c
index 54bbb159b061ea89994f1301c50f8b47bed5ccad..10a56ea8828492d66a08e135498150f269e4bc0e 100644
--- a/tests/unistd/dup.c
+++ b/tests/unistd/dup.c
@@ -2,7 +2,7 @@
 #include <fcntl.h>
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(void) {
     creat("dup.out", 0777);
     int fd1 = open("dup.out", 0);
     int fd2 = dup(fd1);
diff --git a/tests/unistd/exec.c b/tests/unistd/exec.c
index 732ed00aec4047ac3ec2b5712e39ef0da5983bee..fd603471ef4d54b92dbaa33bbbc618b996e5ac4c 100644
--- a/tests/unistd/exec.c
+++ b/tests/unistd/exec.c
@@ -1,7 +1,7 @@
 #include <unistd.h>
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(void) {
     char* args[] = {"sh", "-c", "echo 'exec works :D'", NULL};
     execv("/bin/sh", args);
     perror("execv");
diff --git a/tests/unistd/fchdir.c b/tests/unistd/fchdir.c
index e89c5ef5937794acd437a56e969eeec3cd4abbef..07256cf28c64a142b24ee9e782937fb05de10e12 100644
--- a/tests/unistd/fchdir.c
+++ b/tests/unistd/fchdir.c
@@ -2,7 +2,7 @@
 #include <fcntl.h>
 #include <stdio.h>
 
-int main (int argc, char** argv) {
+int main(void) {
     int fd = open("..", 0, 0);
     int status;
     status = fchdir(fd);
diff --git a/tests/unistd/fsync.c b/tests/unistd/fsync.c
index d9f42bd239aabd99308f815d403eceb5f38bb38a..b7d2f76d5880e908f7d6941c77e0264007c72080 100644
--- a/tests/unistd/fsync.c
+++ b/tests/unistd/fsync.c
@@ -2,7 +2,7 @@
 #include <fcntl.h>
 #include <stdio.h>
 
-int main (int argc, char** argv) {
+int main(void) {
     int fd = open(".", 0, 0);
     int status;
     status = fsync(fd);
diff --git a/tests/unistd/ftruncate.c b/tests/unistd/ftruncate.c
index 67f39f4c45dff22799ccfc94fc15b7612878f0ca..05634015c18e47edc9e01a1736337be7b7a64a59 100644
--- a/tests/unistd/ftruncate.c
+++ b/tests/unistd/ftruncate.c
@@ -2,7 +2,7 @@
 #include <fcntl.h>
 #include <stdio.h>
 
-int main (int argc, char** argv) {
+int main(void) {
     int fd = creat("ftruncate.out", 0777);
     int status;
     status = ftruncate(fd, 100);
diff --git a/tests/unistd/getcwd.c b/tests/unistd/getcwd.c
index 0d8e5f108dc608e307a79294c848bb03b8392942..fd5bd60cc5942e5157237eb5d008b831d6f906f9 100644
--- a/tests/unistd/getcwd.c
+++ b/tests/unistd/getcwd.c
@@ -4,7 +4,7 @@
 #include <string.h>
 #include <unistd.h>
 
-int main() {
+int main(void) {
     char first[PATH_MAX];
     getcwd(first, PATH_MAX);
     puts(first);
diff --git a/tests/unistd/gethostname.c b/tests/unistd/gethostname.c
index 02a0b7a7d439db02697b9567583967c864290fef..85119c32f53572f5af1a11c98a7abb2b1283f40a 100644
--- a/tests/unistd/gethostname.c
+++ b/tests/unistd/gethostname.c
@@ -2,7 +2,7 @@
 #include <stdio.h>
 #include <unistd.h>
 
-int main() {
+int main(void) {
     char* hostname = malloc(256);
     if (gethostname(hostname, 256) == 0) {
         printf("Hostname: %s\n", hostname);
diff --git a/tests/unistd/getid.c b/tests/unistd/getid.c
index 774ffea26093b7eba481193bb8f23d91740981c1..b6a8507dc29b5a72e2ae2870a57eabd89db19a41 100644
--- a/tests/unistd/getid.c
+++ b/tests/unistd/getid.c
@@ -1,7 +1,7 @@
 #include <unistd.h>
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(void) {
     gid_t egid = getegid();
     uid_t euid = geteuid();
     gid_t gid = getgid();
diff --git a/tests/unistd/isatty.c b/tests/unistd/isatty.c
index 9647282aa6a1fff298ea0273bf4d0c1396ec6fcf..33855fbaf9bf7ca99723884cd4a471b4d57f6ddd 100644
--- a/tests/unistd/isatty.c
+++ b/tests/unistd/isatty.c
@@ -1,7 +1,7 @@
 #include <stdio.h>
 #include <unistd.h>
 
-int main() {
+int main(void) {
     // 1 is stdout
     if (isatty(1)) {
         puts("'Tis a tty :D");
diff --git a/tests/unistd/link.c b/tests/unistd/link.c
index a39286106f286079ad03fba42ea720f41f493d83..264c2dda5f8ec9c8a1e07f59e58629b21f832a5f 100644
--- a/tests/unistd/link.c
+++ b/tests/unistd/link.c
@@ -3,7 +3,7 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
-int main(int argc, char** argv) {
+int main(void) {
     printf("%ld\n", sizeof(struct stat));
 
     struct stat buf;
diff --git a/tests/unistd/pathconf.c b/tests/unistd/pathconf.c
index f943ec56ef90524f593a74d16c9efac9c05bd992..77cb7d54664e063a17dc39116ad04b7b03452731 100644
--- a/tests/unistd/pathconf.c
+++ b/tests/unistd/pathconf.c
@@ -7,7 +7,7 @@
 	printf("%s (%d): %ld (%d)\n", #N, _PC_ ## N, fpathconf(0, _PC_ ## N), errno); \
 }
 
-int main(){
+int main(void) {
 	PC(LINK_MAX);
 	PC(MAX_CANON);
 	PC(MAX_INPUT);
diff --git a/tests/unistd/pipe.c b/tests/unistd/pipe.c
index 8f0fc71e5c629ea32ecac86f51f1468593d17266..2e1edf2c9e0847f5c03e00d14fa111bb191040a8 100644
--- a/tests/unistd/pipe.c
+++ b/tests/unistd/pipe.c
@@ -3,9 +3,7 @@
 #include <string.h>
 #include <unistd.h>
 
-int main()
-{
-
+int main(void) {
     int pid, pip[2];
     char instring[20];
     char * outstring = "Hello World!";
diff --git a/tests/unistd/rmdir.c b/tests/unistd/rmdir.c
index 97aa50fe1794616f5199a71c330950bb71af7d9b..11a8bd646e21d5b18c9923246a2bfc697288ba53 100644
--- a/tests/unistd/rmdir.c
+++ b/tests/unistd/rmdir.c
@@ -2,7 +2,7 @@
 #include <sys/stat.h>
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(void) {
     mkdir("foo", 0);
     int status = rmdir("foo");
     printf("rmdir exited with status code %d\n", status);
diff --git a/tests/unistd/setid.c b/tests/unistd/setid.c
index cf6abc6c6726b5151b06cf6963343184b8856a02..78b01dda2e9dedb4e5366e1e3a20063b702f95ac 100644
--- a/tests/unistd/setid.c
+++ b/tests/unistd/setid.c
@@ -6,8 +6,7 @@
 #include <unistd.h>
 #include <stdlib.h>
 
-int main( void )
-  {
+int main(void) {
     if( setpgid( getpid(), 0 ) == -1 ) {
         perror( "setpgid" );
     }
@@ -24,4 +23,4 @@ int main( void )
     }
     printf("%d has euid %d and uid %d\n", getpid(), geteuid(), getuid());
     return 0;
-  }
+}
diff --git a/tests/unistd/sleep.c b/tests/unistd/sleep.c
index cf395a783971d7c3be5bfaa9f54b0141d7f5f8ed..df69754dd24e749c51bedd09a89955477ee4058e 100644
--- a/tests/unistd/sleep.c
+++ b/tests/unistd/sleep.c
@@ -2,7 +2,7 @@
 #include <unistd.h>
 #include <stdio.h>
 
-int main(int argc, char** argv) {
+int main(void) {
     sleep(2);
     perror("sleep");
     usleep(1000);
diff --git a/tests/unistd/stat.c b/tests/unistd/stat.c
index 5fd178530d64198af8893015f632b74ac4406321..a0775bc535095d22ac5c5e59a0001fc61e11c9b9 100644
--- a/tests/unistd/stat.c
+++ b/tests/unistd/stat.c
@@ -3,7 +3,7 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
-int main() {
+int main(void) {
     printf("%ld\n", sizeof(struct stat));
 
     struct stat buf;
diff --git a/tests/unistd/sysconf.c b/tests/unistd/sysconf.c
index aa4bf4882f86304dba26f06d086771f88ffd4173..6e53ee3c407d7fe3df37fdb7a061700e60ec3964 100644
--- a/tests/unistd/sysconf.c
+++ b/tests/unistd/sysconf.c
@@ -7,7 +7,7 @@
 	printf("%s (%d): %ld (%d)\n", #N, _SC_ ## N, sysconf(_SC_ ## N), errno); \
 }
 
-int main(){
+int main(void) {
 	SC(ARG_MAX);
 	SC(CHILD_MAX);
 	SC(CLK_TCK);
diff --git a/tests/unistd/write.c b/tests/unistd/write.c
index 5102aca427ed0646c85cdfaa71b4ffdcd9c69c0d..bfc52a920b9d0a34410ebb558e8457b8bce6ed74 100644
--- a/tests/unistd/write.c
+++ b/tests/unistd/write.c
@@ -1,6 +1,6 @@
 #include <unistd.h>
 
-int main(int argc, char ** argv) {
+int main(void) {
     write(STDOUT_FILENO, "Hello World!\n", 13);
     return 0;
 }
diff --git a/tests/waitpid.c b/tests/waitpid.c
index c350e33c6f9a65a834445c1107aa7befa69398a0..0a52eaa45a48ebba29d4d36f9b853522f1a972fc 100644
--- a/tests/waitpid.c
+++ b/tests/waitpid.c
@@ -2,7 +2,7 @@
 #include <unistd.h>
 #include <stdlib.h>
 
-int main(int argc, char** argv) {
+int main(void) {
     pid_t pid = fork();
     if (pid == 0) {
         // child
diff --git a/tests/wchar/mbrtowc.c b/tests/wchar/mbrtowc.c
index 293926d7ed5def7befe3dce8e04c8a3589a31f07..f05f70313a36575c3755a2161fea7c2b6170b881 100644
--- a/tests/wchar/mbrtowc.c
+++ b/tests/wchar/mbrtowc.c
@@ -2,8 +2,7 @@
 #include <string.h>
 #include <wchar.h>
  
-int main(void)
-{
+int main(void) {
     mbstate_t state;
     memset(&state, 0, sizeof state);
     char in[] = u8"z\u00df\u6c34\U0001F34C"; // or u8"zß水🍌"
diff --git a/tests/wchar/mbsrtowcs.c b/tests/wchar/mbsrtowcs.c
index 070cabc3cd748ff156d08765b60611c899dce2cd..15dff0b7e80297cb74a0cf868de4cbe284fa701c 100644
--- a/tests/wchar/mbsrtowcs.c
+++ b/tests/wchar/mbsrtowcs.c
@@ -17,8 +17,7 @@ void print_as_wide(const char* mbstr)
     //wprintf(L"The wide string: %ls \n", &wstr[0]);
 }
 
-int main()
-{
+int main(void) {
     const char* mbstr = u8"z\u00df\u6c34\U0001f34c"; // or u8"zß水🍌"
     print_as_wide(mbstr);
 }
diff --git a/tests/wchar/putwchar.c b/tests/wchar/putwchar.c
index 067c0a4107565cc200a001b22f712e43ec2a39a2..a777854a538b2de7c084b27843f1912acea3bfa2 100644
--- a/tests/wchar/putwchar.c
+++ b/tests/wchar/putwchar.c
@@ -3,8 +3,7 @@
 #include <wchar.h>
 #include <stdlib.h>
 
-int main(void)
-{
+int main(void) {
     wchar_t *wcs = L"zß水🍌";
 
     int i;
diff --git a/tests/wchar/wcrtomb.c b/tests/wchar/wcrtomb.c
index 4bf5dc35746aade08c69befaa6e7f9b68dd35a73..233496ed3771bc5f8be970c6cd3b012fb504e191 100644
--- a/tests/wchar/wcrtomb.c
+++ b/tests/wchar/wcrtomb.c
@@ -2,9 +2,8 @@
 #include <stdio.h>  
 #include <wchar.h> 
 #include <stdlib.h>
-  
-int main( void )  
-{  
+
+int main(void) {
     mbstate_t state;
     memset(&state, 0, sizeof state);
     wchar_t in[] = L"zß水🍌"; // or "z\u00df\u6c34\U0001F34C"