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)