| NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | CONFORMING TO | NOTES | SEE ALSO | COLOPHON | The Linux Programming Interface |
ECVT(3) Linux Programmer's Manual ECVT(3)
ecvt, fcvt - convert a floating-point number to a string
#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
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.
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().
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).
Linux libc4 and libc5 specified the type of ndigits as size_t. Not all
locales use a point as the radix character ("decimal point").
ecvt_r(3), gcvt(3), qecvt(3), setlocale(3), sprintf(3)
This page is part of release 3.32 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can be found
at http://www.kernel.org/doc/man-pages/.
2010-09-20 ECVT(3)
HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface