* io.c (pipe_open): should set prog if argc != 0.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@7518 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,7 @@
+Thu Dec  9 12:31:53 2004  WATANABE Hirofumi  <eban@ruby-lang.org>
+
+	* io.c (pipe_open): should set prog if argc != 0.
+
 Thu Dec  9 10:54:36 2004  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* ext/dbm/dbm.c (fdbm_select): [ruby-dev:25132]

io.c

@@ -2915,7 +2915,8 @@ pipe_open(argc, argv, mode)
 	}
     }
 #else
-    prog = rb_ary_join(rb_ary_new4(argc, argv), rb_str_new2(" "));
+    if (argc)
+	prog = rb_ary_join(rb_ary_new4(argc, argv), rb_str_new2(" "));
     fp = popen(StringValueCStr(prog), mode);
     if (!fp) rb_sys_fail(RSTRING(prog)->ptr);
     fd = fileno(fp);