From 92a04a491505e6e72630d10cdc952903e811d270 Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Wed, 9 Jul 2014 07:19:43 +0000
Subject: [PATCH] io.c: refine error message

* io.c (do_io_advise): more precise error message, with arguments.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46766 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 io.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/io.c b/io.c
index 77460c9a59..731b3054f6 100644
--- a/io.c
+++ b/io.c
@@ -65,6 +65,13 @@
 #if !HAVE_OFF_T && !defined(off_t)
 # define off_t  long
 #endif
+#if SIZEOF_OFF_T > SIZEOF_LONG && defined(HAVE_LONG_LONG)
+# define PRI_OFF_T_PREFIX "ll"
+#elif SIZEOF_OFF_T == SIZEOF_LONG
+# define PRI_OFF_T_PREFIX "l"
+#else
+# define PRI_OFF_T_PREFIX ""
+#endif
 
 #include <sys/stat.h>
 
@@ -8507,7 +8514,12 @@ do_io_advise(rb_io_t *fptr, VALUE advice, off_t offset, off_t len)
     if (rv) {
 	/* posix_fadvise(2) doesn't set errno. On success it returns 0; otherwise
 	   it returns the error code. */
-	rb_syserr_fail_str(rv, fptr->pathv);
+	VALUE message = rb_sprintf("%"PRIsVALUE" "
+				   "(%"PRI_OFF_T_PREFIX"d, "
+				   "%"PRI_OFF_T_PREFIX"d, "
+				   "%"PRIsVALUE")",
+				   fptr->pathv, offset, len, advice);
+	rb_syserr_fail_str(rv, message);
     }
 
     return Qnil;