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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: 

_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 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 3.78 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/.

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