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

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

       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.

       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).

       Standard C library (libc, -lc)

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

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

       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().

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

Linux man-pages 6.9.1                              2024-05-02                                            ecvt(3)

       None.

#include<stdlib.h>[[deprecated]]char*ecvt(doublenumber,intndigits,int*restrictdecpt,int*restrictsign);[[deprecated]]char*fcvt(doublenumber,intndigits,int*restrictdecpt,int*restrictsign);

   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