diff --git a/watch.c b/watch.c
index 048a4507..c438178f 100644
--- a/watch.c
+++ b/watch.c
@@ -60,9 +60,6 @@
 # define isprint(x) ( (x>=' '&&x<='~') || (x>=0xa0) )
 #endif
 
-#ifndef HOST_NAME_MAX
-#define HOST_NAME_MAX 64
-#endif
 
 /* Boolean command line options */
 static int flags;
@@ -380,7 +377,8 @@ static void output_header(char *restrict command, double interval)
 	char *ts = ctime(&t);
 	char *header;
 	char *right_header;
-	char hostname[HOST_NAME_MAX + 1];
+    int max_host_name_len = (int) sysconf(_SC_HOST_NAME_MAX);
+	char hostname[max_host_name_len + 1];
 	int command_columns = 0;	/* not including final \0 */
 
 	gethostname(hostname, sizeof(hostname));