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fcvt(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:
           (_XOPEN_SOURCE >= 500) ! (_POSIX_C_SOURCE >= 200112L)
               || /* Glibc since 2.19: */ _DEFAULT_SOURCE
               || /* Glibc versions <= 2.19: */ _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 │
   └──────────┴───────────────┴─────────────────────┘

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).

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 4.09 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
   https://www.kernel.org/doc/man-pages/.

                              2016-03-15                           ECVT(3)



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