Add argument parsing

main.c

@@ -73,8 +73,20 @@ static int get_input(int num_threads, struct input **res) {
 
 int main(int argc, char *argv[]) {
 	struct input *inputs = NULL;
-	// TODO: Get input to get actual number of inputs. 5 is just for funzies.
-	int num_inputs = get_input(5, &inputs);
+	if (argc < 2 || argc > 3) {
+		printf("%s\n", USAGE_STRING);
+		return -1;
+	} else if (argc == 3) {
+		printf("Not yet implemented.");
+		return -1;
+	}
+
+	int num_threads = strtol(argv[1], NULL, 10);
+	if (errno == ERANGE || (num_threads == 0 && errno == EINVAL)) {
+		printf("Invalid number of threads.\n");
+	}
+
+	int num_inputs = get_input(num_threads, &inputs);
 	for (int i = 0; i < num_inputs; i++) {
 		printf("#%d recipient=%d value=%d\n", i, inputs[i].recipient, inputs[i].value);
 	}

main.h

@@ -5,6 +5,7 @@
 #define MAXTHREAD 10
 // The max size of the input buffer
 #define BUFFER_SIZE 128
+#define USAGE_STRING "./mailbox num_threads [nb]"
 
 // input represents a pair of values inputted at the command line
 struct input {