C89 / ANSI C
1989年，由ANSI釋出，32個
| auto | break | case | char |
|---|---|---|---|
| const | continue | default | do |
| double | else | enum | extern |
| float | for | goto | if |
| int | long | register | return |
| short | signed | sizeof | static |
| struct | switch | typedef | union |
| unsigned | void | volatile | while |
C89裡沒有inline和bool!!!
C90
1990年，被ISO和IEC采納，ISO/IEC 9899:1990
C99
ISO/IEC 9899:1999，新增5個
| inline | restrict | _Bool | _Complex | _Imaginary |
|---|
C11
ISO/IEC 9899:2011，新增7個
| _Alignas | _Alignof | _Atomic | _Static_assert |
|---|---|---|---|
| _Noreturn | _Thread_local | _Generic |