include/linux/kconfig.h

   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 */