The <builtin.h> include file declares the following built-in and intrinsic functions:
| _alloca | _facos | _fsincos | _lrotl | _rotl |
| _clear87 | _fasin | _fyl2x | _llrotl | _rotr |
| _control87 | _fcos | _fyl2xp1 | _lrotr | _srotl |
| _crotl | _fcossin | _f2xm1 | _llrotr | _srotr |
| _crotr | _fpatan | _inp | __lxchg | __sxchg |
| __cxchg | _fptan | _inpd | _outp | _status87 |
| _disable | _fsin | _inpw | _outpd | |
| _enable | _rsqrt | _interrupt | _outpw |
_clear87, _control87, and _status87 are also defined in <float.h>. _alloca is also defined in <stdlib.h> and <malloc.h>.
The functions _inp, _inpd, _inpw, _outp, _outpd, and _outpw are also defined in <conio.h>.
<builtin.h> also includes a declaration for the type size_t.
![]()
<conio.h>
<malloc.h>
<stdlib.h>