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      浮動小数点拡張パート1: 2進浮動小数点算術

      提供: cppreference.com
       
      C
       
      技術仕様書
       
      浮動小数点拡張パート1: 2進浮動小数点
       
      ISO C にマージされました このページで説明している機能は2019年3月に本線の ISO C 標準にマージされました。 (C2x以上)

      C のための浮動小数点拡張パート1: 2進浮動小数点算術 (ISO/IEC TS 18661-1:2014) は、 ISO/IEC/IEEE 60559:2011 (IEEE-754 の現在のリビジョン) によって推奨されている、 C 標準ライブラリのための新しい以下のコンポーネントを定義します。

      __STDC_IEC_60559_BFP__
      		 integer constant of type long and value 201ymmL, replaces __STDC_IEC_559__
      (マクロ定数)
      __STDC_IEC_60559_COMPLEX__
      		 integer constant of type long and value 201ymmL, replaces __STDC_IEC_559_COMPLEX__
      (マクロ定数)
      ヘッダ <limits.h> で定義
      CHAR_WIDTH SCHAR_WIDTH UCHAR_WIDTHSHRT_WIDTH USHRT_WIDTHINT_WIDTH UINT_WIDTHLONG_WIDTH ULONG_WIDTHLLONG_WIDTH ULLONG_WIDTH
      (FP Ext 1 TS)
      		 width, in bits, of the corresponding type
      (マクロ定数)
      ヘッダ <float.h> で定義
      (FP Ext 1 TS)
      		 conversions between all supported binary floating-point types and character sequences with at most CR_DECIMAL_DIG significant decimal digits are correctly rounded (this is at least DECIMAL_DIG + 3)
      (マクロ定数)
      ヘッダ <fenv.h> で定義
      femode_t
      (FP Ext 1 TS)
      		 collection of dynamic floating-point control modes supported by the implementation, including the dynamic rounding direction mode
      (typedef)
      FE_DFL_MODE
      (FP Ext 1 TS)
      		 pointer to the default femode_t
      (マクロ定数)
      FE_SNANS_ALWAYS_SIGNAL
      (FP Ext 1 TS)
      		 defined (as integer constant 1) if sNaN arguments cause the functions that suppress qNaNs, like hypot or fmax, to raise FE_INVALID and return a qNaN
      (マクロ定数)
      (FP Ext 1 TS)
      		 sets the specified floating-point exception flags without causing any side-effects that raising them would
      (関数)
      (FP Ext 1 TS)
      		 tests if given flags are in a saved representation of the floating-point exception flags
      (関数)
      (FP Ext 1 TS)
      		 gets and sets all the implementation’s dynamic floating-point control modes collectively
      (関数)
      ヘッダ <stdint.h> で定義
      INTn_WIDTH UINTn_WIDTHINT_LEASTn_WIDTH UINT_LEASTn_WIDTHINT_FASTn_WIDTH UINT_FASTn_WIDTHINTPTR_WIDTH UINTPTR_WIDTHINTMAX_WIDTH UINTMAX_WIDTHPTRDIFF_WIDTHSIG_ATOMIC_WIDTHSIZE_WIDTHWCHAR_WIDTH WINT_WIDTH
      (FP Ext 1 TS)
      		 width, in bits, of the corresponding type
      (マクロ定数)
      ヘッダ <stdlib.h> で定義
      (FP Ext 1 TS)
      		 convert a single foating-point number to string using the specified snprintf format
      (関数)
      ヘッダ <math.h> で定義
      FP_INT_UPWARDFP_INT_DOWNWARDFP_INT_TOWARDZERO FP_INT_TONEARESTFROMZEROFP_INT_TONEAREST
      (FP Ext 1 TS)
      		 rounding direction for the functions ceil, floor, trunc, round, and roundeven, suitable for use with fromfp family of functions
      (マクロ定数)
      FP_LLOGB0
      (FP Ext 1 TS)
      		 value returned by llogb if the argument is zero
      (マクロ定数)
      FP_LLOGBNAN
      (FP Ext 1 TS)
      		 value returned by llogb if the argument is NaN
      (マクロ定数)
      (FP Ext 1 TS)
      		 represents a signalling NaN for float, double, long double respectively
      (マクロ定数)
      FP_FAST_FADD FP_FAST_FADDL FP_FAST_DADDLFP_FAST_FSUB FP_FAST_FSUBL FP_FAST_DSUBLFP_FAST_FMUL FP_FAST_FMULL FP_FAST_DMULLFP_FAST_FDIV FP_FAST_FDIVL FP_FAST_DDIVLFP_FAST_FFMA FP_FAST_FFMAL FP_FAST_DFMALFP_FAST_FSQRT FP_FAST_FSQRTL FP_FAST_DSQRTL
      (FP Ext 1 TS)
      		 if defined, indicates that the corresponding function executes faster than the equivalent function in a larger type followed by a cast to target type
      (マクロ定数)
      iseqsig
      (FP Ext 1 TS)

      (関数マクロ)
      iscanonical
      (FP Ext 1 TS)
      		 tests if the floating-point value is canonical
      (関数マクロ)
      issignaling
      (FP Ext 1 TS)
      		 tests if the floating-point value is a signalling NaN
      (関数マクロ)
      issubnormal
      (FP Ext 1 TS)
      		 tests if the floating-point value is subnormal
      (関数マクロ)
      iszero
      (FP Ext 1 TS)
      		 tests if the floating-point value is a zero (positive, negative, unsigned)
      (関数マクロ)
      (FP Ext 1 TS)
      		 round to signed integer using the specified rounding direction
      (関数)
      (FP Ext 1 TS)
      		 round to unsigned integer using the specified rounding direction
      (関数)
      (FP Ext 1 TS)
      		 round to signed integer using the specified rounding direction, reporting inexactness
      (関数)
      (FP Ext 1 TS)
      		 round to unsigned integer using the specified rounding direction, reporting inexactness
      (関数)
      (FP Ext 1 TS)
      		 rounds to nearest, halfway cases to even
      (関数)
      (FP Ext 1 TS)
      		 equivalent to logb except the return type is long
      (関数)
      (FP Ext 1 TS)
      		 returns the value of their argument of maximum magnitude
      (関数)
      (FP Ext 1 TS)
      		 returns the value of their argument of minimum magnitude
      (関数)
      (FP Ext 1 TS)
      		 returns the next greater representable floating-point value
      (関数)
      (FP Ext 1 TS)
      		 returns the next smaller representable floating-point value
      (関数)
      (FP Ext 1 TS)
      		 calculates x+y as if in infinite precision and rounded once to target type
      (関数)
      (FP Ext 1 TS)
      		 calculates x-y as if in infinite precision and rounded once to target type
      (関数)
      (FP Ext 1 TS)
      		 calculates x*y as if in infinite precision and rounded once to target type
      (関数)
      (FP Ext 1 TS)
      		 calculates x/y as if in infinite precision and rounded once to target type
      (関数)
      (FP Ext 1 TS)
      		 calculates the same as fma as if in infinite precision and rounded once to target type
      (関数)
      (FP Ext 1 TS)
      		 calculates the same as sqrt as if in infinite precision and rounded once to target type
      (関数)
      (FP Ext 1 TS)
      		 orders two floating-point values using the ISO 60559 total order relation
      (関数)
      (FP Ext 1 TS)
      		 orders the magnitudes of two floating-point values using the ISO 60559 total order relation
      (関数)
      (FP Ext 1 TS)
      		 obtains the ISO 60559 canonical binary encoding of the given floating-point value
      (関数)
      (FP Ext 1 TS)
      		 extracts the payload from the given NaN value
      (関数)
      (FP Ext 1 TS)
      		 creates a quiet NaN with the specified payload
      (関数)
      (FP Ext 1 TS)
      		 creates a signalling NaN with the specified payload
      (関数)
      ヘッダ <tgmath.h> で定義
      roundeven
      (FP Ext 1 TS)
      		 generic overload of roundeven
      (関数)
      llogb
      (FP Ext 1 TS)
      		 generic overload of llogb
      (関数)
      fmaxmag
      (FP Ext 1 TS)
      		 generic overload of fmaxmag
      (関数)
      fminmag
      (FP Ext 1 TS)
      		 generic overload of fminmag
      (関数)
      nextup
      (FP Ext 1 TS)
      		 generic overload of nextup
      (関数)
      nextdown
      (FP Ext 1 TS)
      		 generic overload of nextdown
      (関数)
      fromfp
      (FP Ext 1 TS)
      		 generic overload of fromfp
      (関数)
      ufromfp
      (FP Ext 1 TS)
      		 generic overload of ufromfp
      (関数)
      fromfpx
      (FP Ext 1 TS)
      		 generic overload of fromfpx
      (関数)
      ufromfpx
      (FP Ext 1 TS)
      		 generic overload of ufromfpx
      (関数)
      nextdown
      (FP Ext 1 TS)
      		 generic overload of nextdown
      (関数)
      totalorder
      (FP Ext 1 TS)
      		 generic overload of totalorder
      (関数)
      totalordermag
      (FP Ext 1 TS)
      		 generic overload of totalordermag
      (関数)
      fadd
      (FP Ext 1 TS)
      		 generic overload of fadd
      (関数)
      dadd
      (FP Ext 1 TS)
      		 generic overload of dadd
      (関数)
      fsub
      (FP Ext 1 TS)
      		 generic overload of fsub
      (関数)
      dsub
      (FP Ext 1 TS)
      		 generic overload of dsub
      (関数)
      fmul
      (FP Ext 1 TS)
      		 generic overload of fmul
      (関数)
      dmul
      (FP Ext 1 TS)
      		 generic overload of dmul
      (関数)
      fdiv
      (FP Ext 1 TS)
      		 generic overload of fdiv
      (関数)
      ddiv
      (FP Ext 1 TS)
      		 generic overload of ddiv
      (関数)
      ffma
      (FP Ext 1 TS)
      		 generic overload of ffma
      (関数)
      dfma
      (FP Ext 1 TS)
      		 generic overload of dfma
      (関数)
      fsqrt
      (FP Ext 1 TS)
      		 generic overload of fsqrt
      (関数)
      dsqrt
      (FP Ext 1 TS)
      		 generic overload of dsqrt
      (関数)

      [編集]ノート

      標準 C のマクロ __STDC_IEC_559__ および __STDC_IEC_559_COMPLEX__ はこの技術仕様書によって時代遅れになります。

      この拡張によって C のライブラリに追加される関数およびマクロはすべて、対応するヘッダがインクルードされる前にマクロ __STDC_WANT_IEC_60559_BFP_EXT__ が定義されている場合にのみ宣言されます。

      標準ライブラリへの追加に加えて、 ISO/IEC TS 18661-1:2014 はコア言語に対する多数の変更を行います。 特に、浮動小数点制御を静的なもの (新しい #pragma STDC FENV_ROUND によって制御される) と動的なもの (fesetround によって制御される) に分割します。 <math.h> のほとんどの関数は、設定されていれば、動的な丸めモードよりも静的な丸めモードを尊重します。

      This section is incomplete
      Reason: add to the pragma page or describe the pragma in full here?
      「https://ja.cppreference.com/mwiki/index.php?title=c/experimental/fpext1&oldid=44433」から取得
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