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   ecvt    ( 3 )

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Имя (Name)

ecvt, fcvt - convert a floating-point number to a string

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Синопсис (Synopsis)

#include <stdlib.h>

       char *ecvt(double number, int ndigits, int *restrict decpt,
                  int *restrict sign);
       char *fcvt(double number, int ndigits, int *restrict decpt,
                  int *restrict sign);

   Feature Test Macro Requirements for glibc (see
   feature_test_macros(7)):

       ecvt(), fcvt():
           Since glibc 2.17
               (_XOPEN_SOURCE >= 500 && ! (_POSIX_C_SOURCE >= 200809L))
                   || /* Glibc >= 2.20 */ _DEFAULT_SOURCE
                   || /* Glibc <= 2.19 */ _SVID_SOURCE
           Glibc versions 2.12 to 2.16:
               (_XOPEN_SOURCE >= 500 && ! (_POSIX_C_SOURCE >= 200112L))
                   || _SVID_SOURCE
           Before glibc 2.12:
               _SVID_SOURCE || _XOPEN_SOURCE >= 500

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Описание (Description)

The ecvt() function converts number to a null-terminated string
       of ndigits digits (where ndigits is reduced to a system-specific
       limit determined by the precision of a double), and returns a
       pointer to the string.  The high-order digit is nonzero, unless
       number is zero.  The low order digit is rounded.  The string
       itself does not contain a decimal point; however, the position of
       the decimal point relative to the start of the string is stored
       in *decpt.  A negative value for *decpt means that the decimal
       point is to the left of the start of the string.  If the sign of
       number is negative, *sign is set to a nonzero value, otherwise it
       is set to 0.  If number is zero, it is unspecified whether *decpt
       is 0 or 1.

       The fcvt() function is identical to ecvt(), except that ndigits
       specifies the number of digits after the decimal point.

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Возвращаемое значение (Return value)

Both the ecvt() and fcvt() functions return a pointer to a static
       string containing the ASCII representation of number.  The static
       string is overwritten by each call to ecvt() or fcvt().

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Атрибуты (Attributes)

For an explanation of the terms used in this section, see
       attributes(7).

       ┌──────────────────────────┬───────────────┬─────────────────────┐
       │Interface                 │ Attribute     │ Value               │
       ├──────────────────────────┼───────────────┼─────────────────────┤
       │ecvt()                    │ Thread safety │ MT-Unsafe race:ecvt │
       ├──────────────────────────┼───────────────┼─────────────────────┤
       │fcvt()                    │ Thread safety │ MT-Unsafe race:fcvt │
       └──────────────────────────┴───────────────┴─────────────────────┘

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Стандарты (Conforming to)

SVr2; marked as LEGACY in POSIX.1-2001.  POSIX.1-2008 removes the
       specifications of ecvt() and fcvt(), recommending the use of
       sprintf(3) instead (though snprintf(3) may be preferable).

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Примечание (Note)

Not all locales use a point as the radix character ("decimal
       point").

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Смотри также (See also)

ecvt_r(3), gcvt(3), qecvt(3), setlocale(3), sprintf(3)

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