Added command-line options to change the verbosity level

src/main.c

@@ -1,5 +1,34 @@
+#define _GNU_SOURCE
 #include <criterion/criterion.h>
+#include <criterion/logging.h>
+#include <stdio.h>
+#include <getopt.h>
+
+# define USAGE                                          \
+    "usage: %s OPTIONS\n"                               \
+    "options: \n"                                       \
+    "    -h or --help: prints this message\n"           \
+    "    --verbose [level]: sets verbosity to level\n"
+
+int print_usage(char *progname) {
+    fprintf(stderr, USAGE, progname);
+    return 0;
+}
+
+int main(int argc, char *argv[]) {
+    static struct option opts[] = {
+        {"verbose", optional_argument,  0, 'v'},
+        {"help",    no_argument,        0, 'h'},
+        {0,         0,                  0,  0 }
+    };
+
+    for (int c; (c = getopt_long(argc, argv, "h", opts, NULL)) != -1;) {
+        switch (c) {
+            case 'v': logging_threshold = atoi(optarg ?: "1"); break;
+            case 'h':
+            default : return print_usage(argv[0]);
+        }
+    }
 
-int main(void) {
     return criterion_run_all_tests();
 }