C has had _Bool natively since the 1999 ISO standard (24 years ago). The standard header <stdbool.h> has "#define bool _Bool". (The ugly name "_Bool" was chosen

C has had _Bool natively since the 1999 ISO standard (24 years ago). The standard header <stdbool.h> has "#define bool _Bool". (The ugly name "_Bool" was chosen to avoid conflicting with existing code.) The upcoming C23 standard will define "bool" as a keyword.