freebsd-dev/config/kernel-kobj-name-len.m4
Brian Behlendorf 79713039a2 Fix gcc configure warnings
Newer versions of gcc are getting smart enough to detect the sloppy
syntax used for the autoconf tests.  It is now generating warnings
for unused/undeclared variables.  Newer version of gcc even have
the -Wunused-but-set-variable option set by default.  This isn't a
problem except when -Werror is set and they get promoted to an error.
In this case the autoconf test will return an incorrect result which
will result in a build failure latter on.

To handle this I'm tightening up many of the autoconf tests to
explicitly mark variables as unused to suppress the gcc warning.
Remember, all of the autoconf code can never actually be run we
just want to get a clean build error to detect which APIs are
available.  Never using a variable is absolutely fine for this.

Closes #176
2011-04-19 10:10:47 -07:00

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dnl #
dnl # 2.6.27 API change,
dnl # kobject KOBJ_NAME_LEN static limit removed. All users of this
dnl # constant were removed prior to 2.6.27, but to be on the safe
dnl # side this check ensures the constant is undefined.
dnl #
AC_DEFUN([ZFS_AC_KERNEL_KOBJ_NAME_LEN], [
AC_MSG_CHECKING([whether kernel defines KOBJ_NAME_LEN])
ZFS_LINUX_TRY_COMPILE([
#include <linux/kobject.h>
],[
int val __attribute__ ((unused));
val = KOBJ_NAME_LEN;
],[
AC_MSG_RESULT([yes])
AC_DEFINE(HAVE_KOBJ_NAME_LEN, 1,
[kernel defines KOBJ_NAME_LEN])
],[
AC_MSG_RESULT([no])
])
])