ecvt(3) - Linux manual page (original) (raw)

ecvt(3) Library Functions Manual ecvt(3)

NAME top

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

LIBRARY top

   Standard C library (_libc_, _-lc_)

SYNOPSIS top

   **#include <stdlib.h>**

   **[[deprecated]] char *ecvt(double** _number_**, int** _ndigits_**,**
                             **int *restrict** _decpt_**, int *restrict** _sign_**);**
   **[[deprecated]] char *fcvt(double** _number_**, int** _ndigits_**,**
                             **int *restrict** _decpt_**, int *restrict** _sign_**);**

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

   **ecvt**(), **fcvt**():
       Since glibc 2.17
           (_XOPEN_SOURCE >= 500 && ! (_POSIX_C_SOURCE >= 200809L))
               || /* glibc >= 2.20 */ _DEFAULT_SOURCE
               || /* glibc <= 2.19 */ _SVID_SOURCE
       glibc 2.12 to glibc 2.16:
           (_XOPEN_SOURCE >= 500 && ! (_POSIX_C_SOURCE >= 200112L))
               || _SVID_SOURCE
       Before glibc 2.12:
           _SVID_SOURCE || _XOPEN_SOURCE >= 500

DESCRIPTION top

   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 top

   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 top

   For an explanation of the terms used in this section, see
   [attributes(7)](../man7/attributes.7.html).
   ┌──────────────────────────┬───────────────┬─────────────────────┐
   │ **Interface** │ **Attribute** │ **Value** │
   ├──────────────────────────┼───────────────┼─────────────────────┤
   │ **ecvt**()                   │ Thread safety │ MT-Unsafe race:ecvt │
   ├──────────────────────────┼───────────────┼─────────────────────┤
   │ **fcvt**()                   │ Thread safety │ MT-Unsafe race:fcvt │
   └──────────────────────────┴───────────────┴─────────────────────┘

STANDARDS top

   None.

HISTORY top

   SVr2; marked as LEGACY in POSIX.1-2001.  POSIX.1-2008 removes the
   specifications of **ecvt**() and **fcvt**(), recommending the use of
   [sprintf(3)](../man3/sprintf.3.html) instead (though [snprintf(3)](../man3/snprintf.3.html) may be preferable).

NOTES top

   Not all locales use a point as the radix character ("decimal
   point").

SEE ALSO top

   [ecvt_r(3)](../man3/ecvt%5Fr.3.html), [gcvt(3)](../man3/gcvt.3.html), [qecvt(3)](../man3/qecvt.3.html), [setlocale(3)](../man3/setlocale.3.html), [sprintf(3)](../man3/sprintf.3.html)

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Linux man-pages 6.10 2024-07-23 ecvt(3)

Pages that refer to this page:ecvt_r(3), gcvt(3), qecvt(3)