modernc.org/cc@v1.0.1/v2/headers/linux_arm/usr/include/arm-linux-gnueabihf/bits/huge_valf.h (about)

     1  /* `HUGE_VALF' constant for IEEE 754 machines (where it is infinity).
     2     Used by <stdlib.h> and <math.h> functions for overflow.
     3     Copyright (C) 1992-2016 Free Software Foundation, Inc.
     4     This file is part of the GNU C Library.
     5  
     6     The GNU C Library is free software; you can redistribute it and/or
     7     modify it under the terms of the GNU Lesser General Public
     8     License as published by the Free Software Foundation; either
     9     version 2.1 of the License, or (at your option) any later version.
    10  
    11     The GNU C Library is distributed in the hope that it will be useful,
    12     but WITHOUT ANY WARRANTY; without even the implied warranty of
    13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    14     Lesser General Public License for more details.
    15  
    16     You should have received a copy of the GNU Lesser General Public
    17     License along with the GNU C Library; if not, see
    18     <http://www.gnu.org/licenses/>.  */
    19  
    20  #ifndef _MATH_H
    21  #error "Never use <bits/huge_valf.h> directly; include <math.h> instead."
    22  #endif
    23  
    24  /* IEEE positive infinity (-HUGE_VAL is negative infinity).  */
    25  
    26  #if __GNUC_PREREQ(3,3)
    27  #define HUGE_VALF	(__builtin_huge_valf())
    28  #elif __GNUC_PREREQ(2,96)
    29  #define HUGE_VALF	(__extension__ 0x1.0p255f)
    30  #elif defined __GNUC__
    31  
    32  #define HUGE_VALF \
    33    (__extension__							      \
    34     ((union { unsigned __l __attribute__((__mode__(__SI__))); float __d; })    \
    35      { __l: 0x7f800000UL }).__d)
    36  
    37  #else				/* not GCC */
    38  
    39  typedef union {
    40  	unsigned char __c[4];
    41  	float __f;
    42  } __huge_valf_t;
    43  
    44  #if __BYTE_ORDER == __BIG_ENDIAN
    45  #define __HUGE_VALF_bytes	{ 0x7f, 0x80, 0, 0 }
    46  #endif
    47  #if __BYTE_ORDER == __LITTLE_ENDIAN
    48  #define __HUGE_VALF_bytes	{ 0, 0, 0x80, 0x7f }
    49  #endif
    50  
    51  static __huge_valf_t __huge_valf = { __HUGE_VALF_bytes };
    52  
    53  #define HUGE_VALF	(__huge_valf.__f)
    54  
    55  #endif				/* GCC.  */