NAME

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

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <stdlib.h>

       [[deprecated]] char *ecvt(double number, int ndigits,
                                 int *restrict decpt, int *restrict sign);
       [[deprecated]] 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 2.12 to glibc 2.16:
               (_XOPEN_SOURCE >= 500 && ! (_POSIX_C_SOURCE >= 200112L))
                   || _SVID_SOURCE
           Before glibc 2.12:
               _SVID_SOURCE || _XOPEN_SOURCE >= 500

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.

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().

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 │
       └───────────────────────────────────────────────────┴───────────────┴─────────────────────┘

STANDARDS

       None.

HISTORY

       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).

NOTES

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

SEE ALSO

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