1ECVT(3)                    Linux Programmer's Manual                   ECVT(3)
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NAME

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

9       #include <stdlib.h>
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11       char *ecvt(double number, int ndigits, int *decpt, int *sign);
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13       char *fcvt(double number, int ndigits, int *decpt, int *sign);
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15   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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17       ecvt(), fcvt(): _SVID_SOURCE || _XOPEN_SOURCE >= 500
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DESCRIPTION

20       The  ecvt()  function  converts  number  to a null-terminated string of
21       ndigits digits (where ndigits is reduced  to  a  system-specific  limit
22       determined  by the precision of a double), and returns a pointer to the
23       string.  The high-order digit is non-zero, unless number is zero.   The
24       low order digit is rounded.  The string itself does not contain a deci‐
25       mal point; however, the position of the decimal point relative  to  the
26       start  of  the string is stored in *decpt.  A negative value for *decpt
27       means that the decimal point is to the left of the start of the string.
28       If  the  sign  of number is negative, *sign is set to a non-zero value,
29       otherwise it is set to 0.  If number is zero, it is unspecified whether
30       *decpt is 0 or 1.
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32       The  fcvt() function is identical to ecvt(), except that ndigits speci‐
33       fies the number of digits after the decimal point.
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RETURN VALUE

36       Both the ecvt() and fcvt() functions  return  a  pointer  to  a  static
37       string  containing  the  ASCII  representation  of  number.  The static
38       string is overwritten by each call to ecvt() or fcvt().
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CONFORMING TO

41       SVr2; marked as LEGACY in POSIX.1-2001.  POSIX.1-2008 removes the spec‐
42       ifications  of  ecvt()  and  fcvt(), recommending the use of sprintf(3)
43       instead (though snprintf(3) may be preferable).
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NOTES

46       Linux libc4 and libc5 specified the type of ndigits as size_t.  Not all
47       locales use a point as the radix character ("decimal point").
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SEE ALSO

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

53       This  page  is  part of release 3.22 of the Linux man-pages project.  A
54       description of the project, and information about reporting  bugs,  can
55       be found at http://www.kernel.org/doc/man-pages/.
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59                                  2009-03-15                           ECVT(3)
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