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authorRusty Russell <rusty@rustcorp.com.au>2012-02-22 14:59:32 +1030
committerAmitay Isaacs <amitay@gmail.com>2012-03-07 13:16:16 +1100
commit361f3ea9ee577c5a3e2fed687a0b417b257c31de (patch)
tree6d356c3aa64317c609ff4e208be76e18996a55f8 /lib/ccan/check_type/check_type.h
parent4f5412dda687c3ff76b426842bf284d01d56a997 (diff)
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lib/ccan: import failtest and required ccan modules for TDB2 unit tests.
New modules: failtest, list, time, read_write_all and tlist. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'lib/ccan/check_type/check_type.h')
-rw-r--r--lib/ccan/check_type/check_type.h63
1 files changed, 63 insertions, 0 deletions
diff --git a/lib/ccan/check_type/check_type.h b/lib/ccan/check_type/check_type.h
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+++ b/lib/ccan/check_type/check_type.h
@@ -0,0 +1,63 @@
+#ifndef CCAN_CHECK_TYPE_H
+#define CCAN_CHECK_TYPE_H
+#include "config.h"
+
+/**
+ * check_type - issue a warning or build failure if type is not correct.
+ * @expr: the expression whose type we should check (not evaluated).
+ * @type: the exact type we expect the expression to be.
+ *
+ * This macro is usually used within other macros to try to ensure that a macro
+ * argument is of the expected type. No type promotion of the expression is
+ * done: an unsigned int is not the same as an int!
+ *
+ * check_type() always evaluates to 0.
+ *
+ * If your compiler does not support typeof, then the best we can do is fail
+ * to compile if the sizes of the types are unequal (a less complete check).
+ *
+ * Example:
+ * // They should always pass a 64-bit value to _set_some_value!
+ * #define set_some_value(expr) \
+ * _set_some_value((check_type((expr), uint64_t), (expr)))
+ */
+
+/**
+ * check_types_match - issue a warning or build failure if types are not same.
+ * @expr1: the first expression (not evaluated).
+ * @expr2: the second expression (not evaluated).
+ *
+ * This macro is usually used within other macros to try to ensure that
+ * arguments are of identical types. No type promotion of the expressions is
+ * done: an unsigned int is not the same as an int!
+ *
+ * check_types_match() always evaluates to 0.
+ *
+ * If your compiler does not support typeof, then the best we can do is fail
+ * to compile if the sizes of the types are unequal (a less complete check).
+ *
+ * Example:
+ * // Do subtraction to get to enclosing type, but make sure that
+ * // pointer is of correct type for that member.
+ * #define container_of(mbr_ptr, encl_type, mbr) \
+ * (check_types_match((mbr_ptr), &((encl_type *)0)->mbr), \
+ * ((encl_type *) \
+ * ((char *)(mbr_ptr) - offsetof(enclosing_type, mbr))))
+ */
+#if HAVE_TYPEOF
+#define check_type(expr, type) \
+ ((typeof(expr) *)0 != (type *)0)
+
+#define check_types_match(expr1, expr2) \
+ ((typeof(expr1) *)0 != (typeof(expr2) *)0)
+#else
+#include <ccan/build_assert/build_assert.h>
+/* Without typeof, we can only test the sizes. */
+#define check_type(expr, type) \
+ BUILD_ASSERT_OR_ZERO(sizeof(expr) == sizeof(type))
+
+#define check_types_match(expr1, expr2) \
+ BUILD_ASSERT_OR_ZERO(sizeof(expr1) == sizeof(expr2))
+#endif /* HAVE_TYPEOF */
+
+#endif /* CCAN_CHECK_TYPE_H */