golden hour

/usr/include/bits

File/Folder	Size	Actions
a.out.h	268 B
byteswap-16.h	1.69 KB
byteswap.h	5.56 KB
cmathcalls.h	4.7 KB
confname.h	23.19 KB
dirent.h	1.69 KB
dlfcn.h	2.47 KB
elfclass.h	426 B
endian.h	176 B
environments.h	3.5 KB
epoll.h	1.11 KB
errno.h	2.11 KB
error.h	2.62 KB
eventfd.h	1.1 KB
fcntl-linux.h	12.55 KB
fcntl.h	2.19 KB
fcntl2.h	5.44 KB
fenv.h	3.94 KB
fenvinline.h	190 B
huge_val.h	1.83 KB
huge_valf.h	1.79 KB
huge_vall.h	1.57 KB
hwcap.h	966 B
in.h	9.01 KB
inf.h	1.03 KB
initspin.h	25 B
inotify.h	1.05 KB
ioctl-types.h	2.41 KB
ioctls.h	4.38 KB
ipc.h	2.01 KB
ipctypes.h	1.14 KB
libc-lock.h	12.54 KB
libio-ldbl.h	1014 B
link.h	4.2 KB
local_lim.h	3.13 KB
locale.h	1.33 KB
math-finite.h	14.24 KB
mathcalls.h	11.3 KB
mathdef.h	2.14 KB
mathinline.h	30.86 KB
mman.h	4.78 KB
monetary-ldbl.h	1.02 KB
mqueue.h	1.22 KB
mqueue2.h	2.11 KB
msq.h	2.47 KB
nan.h	1.54 KB
netdb.h	1.25 KB
param.h	1.4 KB
poll.h	2.04 KB
poll2.h	2.86 KB
posix1_lim.h	4.81 KB
posix2_lim.h	2.82 KB
posix_opt.h	5.65 KB
printf-ldbl.h	986 B
pthreadtypes.h	6.33 KB
resource.h	9.21 KB
sched.h	7.37 KB
select.h	2.08 KB
select2.h	1.4 KB
sem.h	2.53 KB
semaphore.h	1.21 KB
setjmp.h	1.26 KB
setjmp2.h	1.67 KB
shm.h	3.44 KB
sigaction.h	2.79 KB
sigcontext.h	4.08 KB
siginfo.h	9.81 KB
signalfd.h	1.04 KB
signum.h	3.34 KB
sigset.h	4.48 KB
sigstack.h	1.49 KB
sigthread.h	1.64 KB
sockaddr.h	1.5 KB
socket.h	12.6 KB
socket2.h	2.95 KB
socket_type.h	2.16 KB
stab.def	8.82 KB
stat.h	7.46 KB
statfs.h	1.89 KB
statvfs.h	3.34 KB
stdio-ldbl.h	3.11 KB
stdio-lock.h	2.14 KB
stdio.h	5.45 KB
stdio2.h	12.36 KB
stdio_lim.h	1.34 KB
stdlib-float.h	1.12 KB
stdlib-ldbl.h	1.36 KB
stdlib.h	5.53 KB
string.h	56.48 KB
string2.h	46.08 KB
string3.h	4.38 KB
sys_errlist.h	1.19 KB
syscall.h	43.03 KB
sysctl.h	893 B
syslog-ldbl.h	1.17 KB
syslog-path.h	1.03 KB
syslog.h	1.66 KB
termios.h	5.23 KB
time.h	3.35 KB
timerfd.h	1.08 KB
timex.h	4.36 KB
types.h	7.55 KB
typesizes.h	3.15 KB
uio.h	2.42 KB
unistd.h	13.07 KB
ustat.h	1.06 KB
utmp.h	3.87 KB
utmpx.h	3.38 KB
utsname.h	1.19 KB
waitflags.h	1.61 KB
waitstatus.h	3.49 KB
wchar-ldbl.h	2.45 KB
wchar.h	1.11 KB
wchar2.h	20.04 KB
wordsize.h	327 B
xopen_lim.h	3.68 KB

Edit: fenv.h

/* Copyright (C) 1997-2012 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#ifndef _FENV_H
# error "Never use <bits/fenv.h> directly; include <fenv.h> instead."
#endif

/* Define bits representing the exception.  We use the bit positions
   of the appropriate bits in the FPU control word.  */
enum
  {
    FE_INVALID =
#define FE_INVALID	0x01
      FE_INVALID,
    __FE_DENORM = 0x02,
    FE_DIVBYZERO =
#define FE_DIVBYZERO	0x04
      FE_DIVBYZERO,
    FE_OVERFLOW =
#define FE_OVERFLOW	0x08
      FE_OVERFLOW,
    FE_UNDERFLOW =
#define FE_UNDERFLOW	0x10
      FE_UNDERFLOW,
    FE_INEXACT =
#define FE_INEXACT	0x20
      FE_INEXACT
  };

#define FE_ALL_EXCEPT \
	(FE_INEXACT | FE_DIVBYZERO | FE_UNDERFLOW | FE_OVERFLOW | FE_INVALID)

/* The ix87 FPU supports all of the four defined rounding modes.  We
   use again the bit positions in the FPU control word as the values
   for the appropriate macros.  */
enum
  {
    FE_TONEAREST =
#define FE_TONEAREST	0
      FE_TONEAREST,
    FE_DOWNWARD =
#define FE_DOWNWARD	0x400
      FE_DOWNWARD,
    FE_UPWARD =
#define FE_UPWARD	0x800
      FE_UPWARD,
    FE_TOWARDZERO =
#define FE_TOWARDZERO	0xc00
      FE_TOWARDZERO
  };

/* Type representing exception flags.  */
typedef unsigned short int fexcept_t;

/* Type representing floating-point environment.  This structure
   corresponds to the layout of the block written by the `fstenv'
   instruction and has additional fields for the contents of the MXCSR
   register as written by the `stmxcsr' instruction.  */
typedef struct
  {
    unsigned short int __control_word;
    unsigned short int __unused1;
    unsigned short int __status_word;
    unsigned short int __unused2;
    unsigned short int __tags;
    unsigned short int __unused3;
    unsigned int __eip;
    unsigned short int __cs_selector;
    unsigned int __opcode:11;
    unsigned int __unused4:5;
    unsigned int __data_offset;
    unsigned short int __data_selector;
    unsigned short int __unused5;
#ifdef __x86_64__
    unsigned int __mxcsr;
#endif
  }
fenv_t;

/* If the default argument is used we use this value.  */
#define FE_DFL_ENV	((const fenv_t *) -1)

#ifdef __USE_GNU
/* Floating-point environment where none of the exception is masked.  */
# define FE_NOMASK_ENV	((const fenv_t *) -2)
#endif

#ifdef __USE_EXTERN_INLINES
__BEGIN_DECLS

/* Optimized versions.  */
extern int __REDIRECT_NTH (__feraiseexcept_renamed, (int), feraiseexcept);
__extern_inline int
__NTH (feraiseexcept (int __excepts))
{
  if (__builtin_constant_p (__excepts)
      && (__excepts & ~(FE_INVALID | FE_DIVBYZERO)) == 0)
    {
      if ((FE_INVALID & __excepts) != 0)
	{
	  /* One example of a invalid operation is 0.0 / 0.0.  */
	  float __f = 0.0;

# ifdef __SSE_MATH__
	  __asm__ __volatile__ ("divss %0, %0 " : : "x" (__f));
# else
	  __asm__ __volatile__ ("fdiv %%st, %%st(0); fwait"
				: "=t" (__f) : "0" (__f));
# endif
	  (void) &__f;
	}
      if ((FE_DIVBYZERO & __excepts) != 0)
	{
	  float __f = 1.0;
	  float __g = 0.0;

# ifdef __SSE_MATH__
	  __asm__ __volatile__ ("divss %1, %0" : : "x" (__f), "x" (__g));
# else
	  __asm__ __volatile__ ("fdivp %%st, %%st(1); fwait"
				: "=t" (__f) : "0" (__f), "u" (__g) : "st(1)");
# endif
	  (void) &__f;
	}

return 0;
    }

return __feraiseexcept_renamed (__excepts);
}

__END_DECLS
#endif