diff --git a/src/interfaces/ecpg/preproc/pgc.l b/src/interfaces/ecpg/preproc/pgc.l
index 60474b0..3dc2453 100644
--- a/src/interfaces/ecpg/preproc/pgc.l
+++ b/src/interfaces/ecpg/preproc/pgc.l
@@ -1556,7 +1556,7 @@ parse_include(void)
 
 		for (ip = include_paths; yyin == NULL && ip != NULL; ip = ip->next)
 		{
-			if (strlen(ip->path) + strlen(yytext) + 3 > MAXPGPATH)
+			if (strlen(ip->path) + strlen(yytext) + 4 > MAXPGPATH)
 			{
 				fprintf(stderr, _("Error: include path \"%s/%s\" is too long on line %d, skipping\n"), ip->path, yytext, yylineno);
 				continue;