Answer by BobbyShaftoe for Is bool a native C type?

No, there is no bool in ISO C90.

Here's a list of keywords in standard C (not C99):

• auto
• break
• case
• char
• const
• continue
• default
• do
• double
• else
• enum
• extern
• float
• for
• goto
• if
• int
• long
• register
• return
• short
• signed
• static
• struct
• switch
• typedef
• union
• unsigned
• void
• volatile
• while

Here's an article discussing some other differences with C as used in the kernel and the standard: http://www.ibm.com/developerworks/linux/library/l-gcc-hacks/index.html