ECVT(3)                             Linux Programmer's Manual                             ECVT(3)



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

SYNOPSIS
       #include <stdlib.h>

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

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

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

       ecvt(), fcvt():
           Since glibc 2.12:
               _SVID_SOURCE ||
                   (_XOPEN_SOURCE >= 500 ||
                       _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED) &&
                   !(_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600)
           Before glibc 2.12:
               _SVID_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED

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
   Multithreading (see pthreads(7))
       The ecvt() and fcvt() functions are not thread-safe.

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 prefer‐
       able).

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)

COLOPHON
       This page is part of release 3.74 of the Linux man-pages project.  A  description  of  the
       project,  information  about  reporting  bugs, and the latest version of this page, can be
       found at http://www.kernel.org/doc/man-pages/.



                                            2014-08-19                                    ECVT(3)