blob: 0d6ae8ee3ad21de21313fde2dc18fdb78da3dcd5 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
|
/* Licensed under LGPLv2.1+ - see LICENSE file for details */
#ifndef CCAN_BUILD_ASSERT_H
#define CCAN_BUILD_ASSERT_H
/**
* BUILD_ASSERT - assert a build-time dependency.
* @cond: the compile-time condition which must be true.
*
* Your compile will fail if the condition isn't true, or can't be evaluated
* by the compiler. This can only be used within a function.
*
* Example:
* #include <stddef.h>
* ...
* static char *foo_to_char(struct foo *foo)
* {
* // This code needs string to be at start of foo.
* BUILD_ASSERT(offsetof(struct foo, string) == 0);
* return (char *)foo;
* }
*/
#define BUILD_ASSERT(cond) \
do { (void) sizeof(char [1 - 2*!(cond)]); } while(0)
/**
* BUILD_ASSERT_OR_ZERO - assert a build-time dependency, as an expression.
* @cond: the compile-time condition which must be true.
*
* Your compile will fail if the condition isn't true, or can't be evaluated
* by the compiler. This can be used in an expression: its value is "0".
*
* Example:
* #define foo_to_char(foo) \
* ((char *)(foo) \
* + BUILD_ASSERT_OR_ZERO(offsetof(struct foo, string) == 0))
*/
#define BUILD_ASSERT_OR_ZERO(cond) \
(sizeof(char [1 - 2*!(cond)]) - 1)
#endif /* CCAN_BUILD_ASSERT_H */
|
