Previous Table of Contents "New C Standard" commentary
floating-constant: decimal-floating-constant hexadecimal-floating-constant
decimal-floating-constant: fractional-constant exponent-partopt floating-suffixopt digit-sequence exponent-part floating-suffixopt
hexadecimal-floating-constant: hexadecimal-prefix hexadecimal-fractional-constant binary-exponent-part floating-suffixopt hexadecimal-prefix hexadecimal-digit-sequence binary-exponent-part floating-suffixopt
. digit-sequence digit-sequence .
exponent-part: e signopt digit-sequence E signopt digit-sequence
sign:one of + -
digit-sequence: digit digit-sequence digit
hexadecimal-fractional-constant: hexadecimal-digit-sequenceopt . hexadecimal-digit-sequence hexadecimal-digit-sequence .
binary-exponent-part: p signopt digit-sequence P signopt digit-sequence
hexadecimal-digit-sequence: hexadecimal-digit hexadecimal-digit-sequence hexadecimal-digit
floating-suffix:one of f l F L
843 A floating constant has a significand part that may be followed by an exponent part and a suffix that specifies its type.
The components of the significand part may include a digit sequence
representing the whole-number part, followed by a period
The components of the exponent part are an
846 Either the whole-number part or the fraction part has to be present;
847 for decimal floating constants, either the period or the exponent part has to be present.
848 The significand part is interpreted as a (decimal or hexadecimal) rational number;
849 the digit sequence in the exponent part is interpreted as a decimal integer.
850 For decimal floating constants, the exponent indicates the power of 10 by which the significand part is to be scaled.
851 For hexadecimal floating constants, the exponent indicates the power of 2 by which the significand part is to be scaled.
For decimal floating constants, and also for hexadecimal floating
For hexadecimal floating constants when
An unsuffixed floating constant has type
If suffixed by the letter
If suffixed by the letter
857 Floating constants are converted to internal format as if at translation-time.
858 The conversion of a floating constant shall not raise an exceptional condition or a floating-point exception at execution time.
859 The implementation should produce a diagnostic message if a hexadecimal constant cannot be represented exactly in its evaluation format;
860 the implementation should then proceed with the translation of the program.
The translation-time conversion of floating constants should match
the execution-time conversion of character strings by library
functions, such as
862 64) The specification for the library functions recommends more accurate conversion than required for floating constants (see 220.127.116.11).
Created at: 2008-01-30 02:39:42
The text from WG14/N1256 is copyright © ISO
Created at: 2008-01-30 02:39:42 The text from WG14/N1256 is copyright © ISO