diff --git a/src/dj.c b/src/dj.c
index 7a2512e..b847b38 100644
--- a/src/dj.c
+++ b/src/dj.c
@@ -23,7 +23,7 @@
 #include <stdio.h> /* fprintf(3), stderr */
 #include <stdlib.h> /* malloc(3), strtol(3), size_t */
 #include <string.h> /* memcpy(3), memmove(3), memset(3) */
-#include <sysexits.h>
+#include <sysexits.h> /* EX_OK, EX_OSERR, EX_USAGE */
 #include <unistd.h> /* close(2), getopt(3), lseek(2), read(2), write(2),
                      * optarg, optind, STDIN_FILENO, STDOUT_FILENO */
 #include <sys/stat.h> /* S_IRGRP, S_IROTH, S_IRUSR, S_IWGRP, S_IWOTH, S_IWUSR */
@@ -176,7 +176,7 @@ int main(int argc, char *argv[]) {
 		io[i].seek = 0;
 	}
 
-	if (!argc < 0) { usage(program_name); }
+	if (!(argc < 0)) { usage(program_name); }
 
 	int c;