C keywords: constexpr (since C23)

(C23)

(C23)

auto

(C23)

break

case

char

const

(C23)  

continue

default

do

double

else

enum

extern

(C23)

float

for

goto

if

(C99)

int

long

(C23)

register

(C99)  

return

short

signed

sizeof

static

(C23)

struct

switch

(C23)

(C23)

typedef

(C23)

(C23)  

union

unsigned

void

volatile

while

(C11*)

(C11*)

(C11)

(C23)

(C99*)

(C99)

(C23)

(C23)

(C23)

(C11)

(C99)

(C11*)

(C11*)

(C11*)