ECVT
Section: Linux Programmer's Manual (3)
Updated: 2016-03-15
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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 4.13 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/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ATTRIBUTES
-
- CONFORMING TO
-
- NOTES
-
- SEE ALSO
-
- COLOPHON
-
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- Running on 
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