* io.c (ioctl_narg_len): don't use _IOC_SIZE macro on Linux.

  On Linux some constants for ioctl(2) doesn't include the size of
  its return value and 16bit value; for example FIONREAD 0x541B.
  Moreover the manual, ioctl_list(2),  says "Note  that  the  size
  bits  are  very unreliable: in lots of cases they are wrong,
  either because of buggy macros using sizeof(sizeof(struct)),
  or because of legacy values."
  So we shouldn't use it.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@33819 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 0 insertions, 2 deletions

diff --git a/io.c b/io.c
index 81da283384..0410e6339f 100644
--- a/io.c
+++ b/io.c
@@ -7956,8 +7956,6 @@ ioctl_narg_len(ioctl_req_t cmd)
 #endif
 #ifdef IOCPARM_LEN
     len = IOCPARM_LEN(cmd);	/* on BSDish systems we're safe */
-#elif defined(_IOC_SIZE)
-    len = _IOC_SIZE(cmd);
 #else
     len = 256;		/* otherwise guess at what's safe */
 #endif