Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
kconfig.h
Go to the documentation of this file.
1 #ifndef __LINUX_KCONFIG_H
2 #define __LINUX_KCONFIG_H
3 
4 #include <generated/autoconf.h>
5 
6 /*
7  * Helper macros to use CONFIG_ options in C/CPP expressions. Note that
8  * these only work with boolean and tristate options.
9  */
10 
11 /*
12  * Getting something that works in C and CPP for an arg that may or may
13  * not be defined is tricky. Here, if we have "#define CONFIG_BOOGER 1"
14  * we match on the placeholder define, insert the "0," for arg1 and generate
15  * the triplet (0, 1, 0). Then the last step cherry picks the 2nd arg (a one).
16  * When CONFIG_BOOGER is not defined, we generate a (... 1, 0) pair, and when
17  * the last step cherry picks the 2nd arg, we get a zero.
18  */
19 #define __ARG_PLACEHOLDER_1 0,
20 #define config_enabled(cfg) _config_enabled(cfg)
21 #define _config_enabled(value) __config_enabled(__ARG_PLACEHOLDER_##value)
22 #define __config_enabled(arg1_or_junk) ___config_enabled(arg1_or_junk 1, 0)
23 #define ___config_enabled(__ignored, val, ...) val
24 
25 /*
26  * IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm',
27  * 0 otherwise.
28  *
29  */
30 #define IS_ENABLED(option) \
31  (config_enabled(option) || config_enabled(option##_MODULE))
32 
33 /*
34  * IS_BUILTIN(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y', 0
35  * otherwise. For boolean options, this is equivalent to
36  * IS_ENABLED(CONFIG_FOO).
37  */
38 #define IS_BUILTIN(option) config_enabled(option)
39 
40 /*
41  * IS_MODULE(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'm', 0
42  * otherwise.
43  */
44 #define IS_MODULE(option) config_enabled(option##_MODULE)
45 
46 #endif /* __LINUX_KCONFIG_H */