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: mathcalls.h

/* Prototype declarations for math functions; helper file for <math.h>.
   Copyright (C) 1996-2003, 2006, 2011, 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/>.  */

/* NOTE: Because of the special way this file is used by <math.h>, this
   file must NOT be protected from multiple inclusion as header files
   usually are.

This file provides prototype declarations for the math functions.
   Most functions are declared using the macro:

__MATHCALL (NAME,[_r], (ARGS...));

This means there is a function `NAME' returning `double' and a function
   `NAMEf' returning `float'.  Each place `_Mdouble_' appears in the
   prototype, that is actually `double' in the prototype for `NAME' and
   `float' in the prototype for `NAMEf'.  Reentrant variant functions are
   called `NAME_r' and `NAMEf_r'.

Functions returning other types like `int' are declared using the macro:

__MATHDECL (TYPE, NAME,[_r], (ARGS...));

This is just like __MATHCALL but for a function returning `TYPE'
   instead of `_Mdouble_'.  In all of these cases, there is still
   both a `NAME' and a `NAMEf' that takes `float' arguments.

Note that there must be no whitespace before the argument passed for
   NAME, to make token pasting work with -traditional.  */

#ifndef _MATH_H
# error "Never include <bits/mathcalls.h> directly; include <math.h> instead."
#endif

/* Trigonometric functions.  */

_Mdouble_BEGIN_NAMESPACE
/* Arc cosine of X.  */
__MATHCALL (acos,, (_Mdouble_ __x));
/* Arc sine of X.  */
__MATHCALL (asin,, (_Mdouble_ __x));
/* Arc tangent of X.  */
__MATHCALL (atan,, (_Mdouble_ __x));
/* Arc tangent of Y/X.  */
__MATHCALL (atan2,, (_Mdouble_ __y, _Mdouble_ __x));

/* Cosine of X.  */
__MATHCALL (cos,, (_Mdouble_ __x));
/* Sine of X.  */
__MATHCALL (sin,, (_Mdouble_ __x));
/* Tangent of X.  */
__MATHCALL (tan,, (_Mdouble_ __x));

/* Hyperbolic functions.  */

/* Hyperbolic cosine of X.  */
__MATHCALL (cosh,, (_Mdouble_ __x));
/* Hyperbolic sine of X.  */
__MATHCALL (sinh,, (_Mdouble_ __x));
/* Hyperbolic tangent of X.  */
__MATHCALL (tanh,, (_Mdouble_ __x));
_Mdouble_END_NAMESPACE

#ifdef __USE_GNU
/* Cosine and sine of X.  */
__MATHDECL (void,sincos,,
	    (_Mdouble_ __x, _Mdouble_ *__sinx, _Mdouble_ *__cosx));
#endif

#if defined __USE_MISC || defined __USE_XOPEN_EXTENDED || defined __USE_ISOC99
__BEGIN_NAMESPACE_C99
/* Hyperbolic arc cosine of X.  */
__MATHCALL (acosh,, (_Mdouble_ __x));
/* Hyperbolic arc sine of X.  */
__MATHCALL (asinh,, (_Mdouble_ __x));
/* Hyperbolic arc tangent of X.  */
__MATHCALL (atanh,, (_Mdouble_ __x));
__END_NAMESPACE_C99
#endif

/* Exponential and logarithmic functions.  */

_Mdouble_BEGIN_NAMESPACE
/* Exponential function of X.  */
__MATHCALL (exp,, (_Mdouble_ __x));

/* Break VALUE into a normalized fraction and an integral power of 2.  */
__MATHCALL (frexp,, (_Mdouble_ __x, int *__exponent));

/* X times (two to the EXP power).  */
__MATHCALL (ldexp,, (_Mdouble_ __x, int __exponent));

/* Natural logarithm of X.  */
__MATHCALL (log,, (_Mdouble_ __x));

/* Base-ten logarithm of X.  */
__MATHCALL (log10,, (_Mdouble_ __x));

/* Break VALUE into integral and fractional parts.  */
__MATHCALL (modf,, (_Mdouble_ __x, _Mdouble_ *__iptr))
     __attribute__ ((__nonnull__ (2)));
_Mdouble_END_NAMESPACE

#ifdef __USE_GNU
/* A function missing in all standards: compute exponent to base ten.  */
__MATHCALL (exp10,, (_Mdouble_ __x));
/* Another name occasionally used.  */
__MATHCALL (pow10,, (_Mdouble_ __x));
#endif

#if defined __USE_MISC || defined __USE_XOPEN_EXTENDED || defined __USE_ISOC99
__BEGIN_NAMESPACE_C99
/* Return exp(X) - 1.  */
__MATHCALL (expm1,, (_Mdouble_ __x));

/* Return log(1 + X).  */
__MATHCALL (log1p,, (_Mdouble_ __x));

/* Return the base 2 signed integral exponent of X.  */
__MATHCALL (logb,, (_Mdouble_ __x));
__END_NAMESPACE_C99
#endif

#ifdef __USE_ISOC99
__BEGIN_NAMESPACE_C99
/* Compute base-2 exponential of X.  */
__MATHCALL (exp2,, (_Mdouble_ __x));

/* Compute base-2 logarithm of X.  */
__MATHCALL (log2,, (_Mdouble_ __x));
__END_NAMESPACE_C99
#endif

/* Power functions.  */

_Mdouble_BEGIN_NAMESPACE
/* Return X to the Y power.  */
__MATHCALL (pow,, (_Mdouble_ __x, _Mdouble_ __y));

/* Return the square root of X.  */
__MATHCALL (sqrt,, (_Mdouble_ __x));
_Mdouble_END_NAMESPACE

#if defined __USE_MISC || defined __USE_XOPEN || defined __USE_ISOC99
__BEGIN_NAMESPACE_C99
/* Return `sqrt(X*X + Y*Y)'.  */
__MATHCALL (hypot,, (_Mdouble_ __x, _Mdouble_ __y));
__END_NAMESPACE_C99
#endif

#if defined __USE_MISC || defined __USE_XOPEN_EXTENDED || defined __USE_ISOC99
__BEGIN_NAMESPACE_C99
/* Return the cube root of X.  */
__MATHCALL (cbrt,, (_Mdouble_ __x));
__END_NAMESPACE_C99
#endif

/* Nearest integer, absolute value, and remainder functions.  */

_Mdouble_BEGIN_NAMESPACE
/* Smallest integral value not less than X.  */
__MATHCALLX (ceil,, (_Mdouble_ __x), (__const__));

/* Absolute value of X.  */
__MATHCALLX (fabs,, (_Mdouble_ __x), (__const__));

/* Largest integer not greater than X.  */
__MATHCALLX (floor,, (_Mdouble_ __x), (__const__));

/* Floating-point modulo remainder of X/Y.  */
__MATHCALL (fmod,, (_Mdouble_ __x, _Mdouble_ __y));

/* Return 0 if VALUE is finite or NaN, +1 if it
   is +Infinity, -1 if it is -Infinity.  */
__MATHDECL_1 (int,__isinf,, (_Mdouble_ __value)) __attribute__ ((__const__));

/* Return nonzero if VALUE is finite and not NaN.  */
__MATHDECL_1 (int,__finite,, (_Mdouble_ __value)) __attribute__ ((__const__));
_Mdouble_END_NAMESPACE

#ifdef __USE_MISC
/* Return 0 if VALUE is finite or NaN, +1 if it
   is +Infinity, -1 if it is -Infinity.  */
__MATHDECL_1 (int,isinf,, (_Mdouble_ __value)) __attribute__ ((__const__));

/* Return nonzero if VALUE is finite and not NaN.  */
__MATHDECL_1 (int,finite,, (_Mdouble_ __value)) __attribute__ ((__const__));

/* Return the remainder of X/Y.  */
__MATHCALL (drem,, (_Mdouble_ __x, _Mdouble_ __y));

/* Return the fractional part of X after dividing out `ilogb (X)'.  */
__MATHCALL (significand,, (_Mdouble_ __x));
#endif /* Use misc.  */

#if defined __USE_MISC || defined __USE_ISOC99
__BEGIN_NAMESPACE_C99
/* Return X with its signed changed to Y's.  */
__MATHCALLX (copysign,, (_Mdouble_ __x, _Mdouble_ __y), (__const__));
__END_NAMESPACE_C99
#endif

#ifdef __USE_ISOC99
__BEGIN_NAMESPACE_C99
/* Return representation of NaN for double type.  */
__MATHCALLX (nan,, (const char *__tagb), (__const__));
__END_NAMESPACE_C99
#endif

/* Return nonzero if VALUE is not a number.  */
__MATHDECL_1 (int,__isnan,, (_Mdouble_ __value)) __attribute__ ((__const__));

#if defined __USE_MISC || defined __USE_XOPEN
/* Return nonzero if VALUE is not a number.  */
__MATHDECL_1 (int,isnan,, (_Mdouble_ __value)) __attribute__ ((__const__));

/* Bessel functions.  */
__MATHCALL (j0,, (_Mdouble_));
__MATHCALL (j1,, (_Mdouble_));
__MATHCALL (jn,, (int, _Mdouble_));
__MATHCALL (y0,, (_Mdouble_));
__MATHCALL (y1,, (_Mdouble_));
__MATHCALL (yn,, (int, _Mdouble_));
#endif

#if defined __USE_MISC || defined __USE_XOPEN || defined __USE_ISOC99
__BEGIN_NAMESPACE_C99
/* Error and gamma functions.  */
__MATHCALL (erf,, (_Mdouble_));
__MATHCALL (erfc,, (_Mdouble_));
__MATHCALL (lgamma,, (_Mdouble_));
__END_NAMESPACE_C99
#endif

#ifdef __USE_ISOC99
__BEGIN_NAMESPACE_C99
/* True gamma function.  */
__MATHCALL (tgamma,, (_Mdouble_));
__END_NAMESPACE_C99
#endif

#if defined __USE_MISC || defined __USE_XOPEN
/* Obsolete alias for `lgamma'.  */
__MATHCALL (gamma,, (_Mdouble_));
#endif

#ifdef __USE_MISC
/* Reentrant version of lgamma.  This function uses the global variable
   `signgam'.  The reentrant version instead takes a pointer and stores
   the value through it.  */
__MATHCALL (lgamma,_r, (_Mdouble_, int *__signgamp));
#endif

#if defined __USE_MISC || defined __USE_XOPEN_EXTENDED || defined __USE_ISOC99
__BEGIN_NAMESPACE_C99
/* Return the integer nearest X in the direction of the
   prevailing rounding mode.  */
__MATHCALL (rint,, (_Mdouble_ __x));

/* Return X + epsilon if X < Y, X - epsilon if X > Y.  */
__MATHCALLX (nextafter,, (_Mdouble_ __x, _Mdouble_ __y), (__const__));
# if defined __USE_ISOC99 && !defined __LDBL_COMPAT
__MATHCALLX (nexttoward,, (_Mdouble_ __x, long double __y), (__const__));
# endif

/* Return the remainder of integer divison X / Y with infinite precision.  */
__MATHCALL (remainder,, (_Mdouble_ __x, _Mdouble_ __y));

# if defined __USE_MISC || defined __USE_ISOC99
/* Return X times (2 to the Nth power).  */
__MATHCALL (scalbn,, (_Mdouble_ __x, int __n));
# endif

/* Return the binary exponent of X, which must be nonzero.  */
__MATHDECL (int,ilogb,, (_Mdouble_ __x));
#endif

#ifdef __USE_ISOC99
/* Return X times (2 to the Nth power).  */
__MATHCALL (scalbln,, (_Mdouble_ __x, long int __n));

/* Round X to integral value in floating-point format using current
   rounding direction, but do not raise inexact exception.  */
__MATHCALL (nearbyint,, (_Mdouble_ __x));

/* Round X to nearest integral value, rounding halfway cases away from
   zero.  */
__MATHCALLX (round,, (_Mdouble_ __x), (__const__));

/* Round X to the integral value in floating-point format nearest but
   not larger in magnitude.  */
__MATHCALLX (trunc,, (_Mdouble_ __x), (__const__));

/* Compute remainder of X and Y and put in *QUO a value with sign of x/y
   and magnitude congruent `mod 2^n' to the magnitude of the integral
   quotient x/y, with n >= 3.  */
__MATHCALL (remquo,, (_Mdouble_ __x, _Mdouble_ __y, int *__quo));

/* Conversion functions.  */

/* Round X to nearest integral value according to current rounding
   direction.  */
__MATHDECL (long int,lrint,, (_Mdouble_ __x));
__MATHDECL (long long int,llrint,, (_Mdouble_ __x));

/* Round X to nearest integral value, rounding halfway cases away from
   zero.  */
__MATHDECL (long int,lround,, (_Mdouble_ __x));
__MATHDECL (long long int,llround,, (_Mdouble_ __x));

/* Return positive difference between X and Y.  */
__MATHCALL (fdim,, (_Mdouble_ __x, _Mdouble_ __y));

/* Return maximum numeric value from X and Y.  */
__MATHCALLX (fmax,, (_Mdouble_ __x, _Mdouble_ __y), (__const__));

/* Return minimum numeric value from X and Y.  */
__MATHCALLX (fmin,, (_Mdouble_ __x, _Mdouble_ __y), (__const__));

/* Classify given number.  */
__MATHDECL_1 (int, __fpclassify,, (_Mdouble_ __value))
     __attribute__ ((__const__));

/* Test for negative number.  */
__MATHDECL_1 (int, __signbit,, (_Mdouble_ __value))
     __attribute__ ((__const__));

/* Multiply-add function computed as a ternary operation.  */
__MATHCALL (fma,, (_Mdouble_ __x, _Mdouble_ __y, _Mdouble_ __z));
#endif /* Use ISO C99.  */

#if defined __USE_MISC || defined __USE_XOPEN_EXTENDED || defined __USE_ISOC99
__END_NAMESPACE_C99
#endif

#if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
/* Return X times (2 to the Nth power).  */
__MATHCALL (scalb,, (_Mdouble_ __x, _Mdouble_ __n));
#endif