kc3-lang/gnulib/doc/posix-headers/float.texi

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• Hash : fda40b61
  Author :
  Date : 2024-08-01T00:46:49
  

  float: Update to mostly guarantee ISO C 23 compliance.
  
  * doc/posix-headers/float.texi: Mention the various portability
  problems.
  * lib/float.in.h (FLT_HAS_SUBNORM, FLT_DECIMAL_DIG, FLT_TRUE_MIN,
  DBL_HAS_SUBNORM, DBL_DECIMAL_DIG, DBL_TRUE_MIN, LDBL_HAS_SUBNORM,
  LDBL_DECIMAL_DIG, LDBL_TRUE_MIN): New macros.
  (gl_LDBL_TRUE_MIN): New declaration.
  (FLT_IS_IEC_60559, FLT_NORM_MAX, FLT_SNAN, GNULIB_defined_FLT_SNAN,
  DBL_IS_IEC_60559, DBL_NORM_MAX, DBL_SNAN, GNULIB_defined_DBL_SNAN,
  LDBL_IS_IEC_60559, LDBL_NORM_MAX, LDBL_SNAN, GNULIB_defined_LDBL_SNAN):
  New macros.
  (gl_FLT_SNAN_t, gl_DBL_SNAN_t, gl_LDBL_SNAN_t): New types.
  (gl_FLT_SNAN, gl_DBL_SNAN, gl_LDBL_SNAN): New declarations.
  * lib/float.c (gl_LDBL_TRUE_MIN): New variable.
  (gl_FLT_SNAN, gl_DBL_SNAN, gl_LDBL_SNAN): New variables.
  * m4/float_h.m4 (gl_FLOAT_H): Add check whether float.h conforms to
  ISO C23. Set REPLACE_FLOAT_SNAN.
  * modules/float (configure.ac): Test also REPLACE_FLOAT_SNAN. Require
  gl_BIGENDIAN.
  * tests/test-float.c: Also check FLT_EVAL_METHOD, FLT_HAS_SUBNORM,
  FLT_DECIMAL_DIG, FLT_IS_IEC_60559, FLT_TRUE_MIN, FLT_NORM_MAX,
  DBL_HAS_SUBNORM, DBL_DECIMAL_DIG, DBL_IS_IEC_60559, DBL_TRUE_MIN,
  DBL_NORM_MAX, LDBL_HAS_SUBNORM, LDBL_DECIMAL_DIG, LDBL_IS_IEC_60559.
  Conditionally check LDBL_TRUE_MIN, LDBL_NORM_MAX.
  Include isnanf-nolibm.h, isnand-nolibm.h, isnanl-nolibm.h.
  (test_float): Check the values of FLT_HAS_SUBNORM, FLT_DECIMAL_DIG,
  FLT_TRUE_MIN, FLT_IS_IEC_60559, FLT_NORM_MAX, FLT_SNAN.
  (test_double): Check the values of DBL_HAS_SUBNORM, DBL_DECIMAL_DIG,
  DBL_TRUE_MIN, DBL_IS_IEC_60559, DBL_NORM_MAX, DBL_SNAN.
  (test_long_double): Check the values of LDBL_HAS_SUBNORM,
  LDBL_DECIMAL_DIG, LDBL_TRUE_MIN, LDBL_IS_IEC_60559, LDBL_NORM_MAX,
  LDBL_SNAN.
  * modules/float-tests (Depends-on): Add isnanf-nolibm, isnand-nolibm,
  isnanl-nolibm.
  

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• doc/posix-headers/float.texi

• @node float.h
  @section @file{float.h}
  
  POSIX specification:@* @url{https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/float.h.html}
  
  Gnulib module: float
  
  Portability problems fixed by Gnulib:
  @itemize
  @item
  The conversion from @code{int} to @code{long double} in incorrect on some
  platforms:
  glibc 2.7 on Linux/SPARC64.
  @item
  The values of @code{LDBL_*} macros are incorrect on some platforms:
  On OpenBSD 4.0 and MirBSD 10, they are the same as the values of the
  @code{DBL_*} macros, although @samp{long double} is a larger type than
  @samp{double}.
  On FreeBSD/x86 6.4, they represent the incorrect 53-bit precision assumptions
  in the compiler, not the real 64-bit precision at runtime.
  On Linux/PowerPC with GCC 4.4, and on AIX 7.1 with GCC 4.2,
  they don't reflect the ``double double'' representation of @code{long double}
  correctly.
  @item
  The macros
  @code{FLT_HAS_SUBNORM}, @code{FLT_DECIMAL_DIG}, @code{FLT_TRUE_MIN},
  @code{DBL_HAS_SUBNORM}, @code{DBL_DECIMAL_DIG}, @code{DBL_TRUE_MIN},
  @code{LDBL_HAS_SUBNORM}, @code{LDBL_DECIMAL_DIG}, @code{LDBL_TRUE_MIN},
  that were added in ISO C 11, are missing on some platforms:
  gcc 4.5.4, clang 7, Solaris 11.3 with Sun C.
  @item
  The macro @code{LDBL_DECIMAL_DIG} is missing on some platforms:
  MSVC 14.
  @item
  The value of macro @code{FLT_TRUE_MIN} is not a @code{float} on some platforms:
  AIX 7.1 with xlc.
  @item
  The macros
  @code{FLT_IS_IEC_60559}, @code{FLT_NORM_MAX}, @code{FLT_SNAN},
  @code{DBL_IS_IEC_60559}, @code{DBL_NORM_MAX}, @code{DBL_SNAN},
  @code{LDBL_IS_IEC_60559}, @code{LDBL_NORM_MAX}, @code{LDBL_SNAN},
  that were added in ISO C 23, are missing on some platforms:
  gcc 14 without @code{-std=c23} or @code{-std=gnu23}, clang 18, musl libc 1.2.5, AIX 7.3 with xlclang, Solaris 11.3 with Sun C, MSVC 14.
  @end itemize
  
  Portability problems not fixed by Gnulib:
  @itemize
  @item
  The macro @code{FLT_ROUNDS} is a constant expression and does not represent
  the current rounding mode on some platforms:
  glibc 2.11, HP-UX 11, mingw.
  @item
  The value of @code{FLT_TRUE_MIN} is not a constant on some platforms:
  FreeBSD/x86.
  @item
  The values of @code{FLT_SNAN}, @code{DBL_SNAN}, @code{LDBL_SNAN} are not
  constants on some platforms:
  AIX 7.3 with xlclang, and all platforms which use the gnulib replacements.
  @end itemize
  

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