From 19fee2e2e075950120573f4063b22fb8082fad0e Mon Sep 17 00:00:00 2001
From: akr <akr@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Tue, 23 Dec 2008 15:22:18 +0000
Subject: * io.c (rb_io_init_copy): call io_seek only if io_tell succeeds.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@20954 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 io.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

(limited to 'io.c')

diff --git a/io.c b/io.c
index eae314b73b..e86a59ae73 100644
--- a/io.c
+++ b/io.c
@@ -5368,6 +5368,7 @@ rb_io_init_copy(VALUE dest, VALUE io)
     rb_io_t *fptr, *orig;
     int fd;
     VALUE write_io;
+    off_t pos;
 
     io = rb_io_get_io(io);
     if (dest == io) return dest;
@@ -5386,7 +5387,9 @@ rb_io_init_copy(VALUE dest, VALUE io)
 
     fd = ruby_dup(orig->fd);
     fptr->fd = fd;
-    io_seek(fptr, io_tell(orig), SEEK_SET);
+    pos = io_tell(orig);
+    if (0 <= pos)
+        io_seek(fptr, pos, SEEK_SET);
     if (fptr->mode & FMODE_BINMODE) {
 	rb_io_binmode(dest);
     }
-- 
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