* 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

1 files changed, 2 insertions, 1 deletions

diff --git a/io.c b/io.c
index 8a6e1f40ef..8256b57782 100644
--- a/io.c
+++ b/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);