To Linux fans,

My inherited code has #ifdef for the variables below. I tried to find the #define for them but could not locate the #define.
If you know where the #define for these variables, please help

__KERNEL__
__ASSEMBLY__
_powerpc64__
CONFIG_64BIT

Thanks in advance

These are typically defined on the command line rather than an include file.

__KERNEL__ is defined in the kernel makefile and is used so that the headers can be used both by kernel/kernel modules and by libraries (it affects what is available in certain header files)
__ASSEMBLY__ is also defined in the kernel makefile when compiling assembler code, so that headers can be used by both assembler and C language files
__powerpc64__ possibly defined by the compiler depending on the cpu architecture being selected
CONFIG_64BIT is defined in the configuration file for the kernel

If you are using your code as part of a kernel module with a typical makefile, then these will all be defined (or not defined) as appropriate.

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