On 06/29/2015 12:25 PM, Alireza Haghdoost wrote:
On Mon, Jun 29, 2015 at 12:50 PM, Jens Axboe <axboe@xxxxxxxxx> wrote:
On 06/29/2015 11:42 AM, Alireza Haghdoost wrote:
Jens,
Sounds like the compiletime_assert() method was not function and is
relying on the optimizer performing dead code elimination to remove
the call to prefix ## suffix
How about this solution: I guess we have to work around it to make it
more portable since it works with C11.
diff --git a/fio-arh/compiler/compiler.h b/fio-arh/compiler/compiler.h
index 40e857c..7c9ba57 100644
--- a/fio-arh/compiler/compiler.h
+++ b/fio-arh/compiler/compiler.h
@@ -33,26 +33,6 @@
1; \
})
-#ifndef __compiletime_error
-#define __compiletime_error(message)
-#endif
-#ifndef __compiletime_error_fallback
-#define __compiletime_error_fallback(condition) do { } while (0)
-#endif
-
-#define __compiletime_assert(condition, msg, prefix, suffix) \
- do { \
- int __cond = !(condition); \
- extern void prefix ## suffix(void) __compiletime_error(msg); \
- if (__cond) \
- prefix ## suffix(); \
- __compiletime_error_fallback(__cond); \
- } while (0)
-
-#define _compiletime_assert(condition, msg, prefix, suffix) \
- __compiletime_assert(condition, msg, prefix, suffix)
-
-#define compiletime_assert(condition, msg) \
- _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
+#define compiletime_assert(condition, msg) _Static_assert(condition, msg)
#endif
But now it's more compiler dependent, which is worse than before. At least
it only broke if people fiddled with the optimizations before, otherwise it
was fine.
Add a configure test for this, use _Static_assert() if it's available, the
old method if not.
Here you are:
diff --git a/fio-arh/compiler/compiler.h b/fio-arh/compiler/compiler.h
index 40e857c..93fdc56 100644
--- a/fio-arh/compiler/compiler.h
+++ b/fio-arh/compiler/compiler.h
@@ -1,5 +1,6 @@
#ifndef FIO_COMPILER_H
#define FIO_COMPILER_H
+#include <assert.h>
#if __GNUC__ >= 4
#include "compiler-gcc4.h"
@@ -33,6 +34,12 @@
1; \
})
+
+#if (__STDC_VERSION__ >= 201112L)
+#define compiletime_assert(condition, msg) _Static_assert(condition, msg)
+#else
+
+
#ifndef __compiletime_error
#define __compiletime_error(message)
#endif
@@ -55,4 +62,7 @@
#define compiletime_assert(condition, msg) \
_compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
+
+#endif
+
#endif
This is not going to work for earlier compilers, in fact it breaks on
even gcc 4.9 here. As I said, this needs to be a configure test. That is
a lot more reliable than this sort of version checking.
--
Jens Axboe
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