NAME

       ecvt, fcvt, gcvt - convert a floating-point number to a string (LEGACY)

SYNOPSIS

       #include <stdlib.h>

       char *ecvt(double value, int ndigit, int *restrict decpt,
              int *restrict sign);
       char *fcvt(double value, int ndigit, int *restrict decpt,
              int *restrict sign);
       char *gcvt(double value, int ndigit, char *buf);

DESCRIPTION

       The ecvt(), fcvt(), and gcvt() functions shall convert floating-point numbers to null-terminated strings.

       The  ecvt()  function  shall  convert value to a null-terminated string of ndigit digits (where ndigit is
       reduced to an unspecified limit determined by the precision of a double) and  return  a  pointer  to  the
       string.  The  high-order  digit  shall  be  non-zero, unless the value is 0. The low-order digit shall be
       rounded in an implementation-defined manner.  The  position  of  the  radix  character  relative  to  the
       beginning of the string shall be stored in the integer pointed to by decpt (negative means to the left of
       the  returned  digits). If value is zero, it is unspecified whether the integer pointed to by decpt would
       be 0 or 1. The radix character shall not be included in the returned string. If the sign of the result is
       negative, the integer pointed to by sign shall be non-zero; otherwise, it shall be 0.

       If the converted value is out of range or is not representable, the contents of the returned  string  are
       unspecified.

       The  fcvt()  function  shall  be  equivalent to ecvt(), except that ndigit specifies the number of digits
       desired after the radix character. The total number of digits in the result string is  restricted  to  an
       unspecified limit as determined by the precision of a double.

       The gcvt() function shall convert value to a null-terminated string (similar to that of the %g conversion
       specification  format  of printf()) in the array pointed to by buf and shall return buf. It shall produce
       ndigit significant digits (limited to an unspecified value determined by the precision of  a  double)  in
       the %f conversion specification format of printf() if possible, or the %e conversion specification format
       of  printf()  (scientific  notation)  otherwise. A minus sign shall be included in the returned string if
       value is less than 0. A radix character shall be included in the returned string if value is not a  whole
       number.   Trailing  zeros  shall  be suppressed where value is not a whole number. The radix character is
       determined by the current locale. If setlocale() has not been called successfully,  the  default  locale,
       POSIX,  is  used.  The  default locale specifies a period ( '.' ) as the radix character.  The LC_NUMERIC
       category determines the value of the radix character within the current locale.

       These functions need not be reentrant. A function that is not required to be reentrant is not required to
       be thread-safe.

RETURN VALUE

       The ecvt() and fcvt() functions shall return a pointer to a null-terminated string of digits.

       The gcvt() function shall return buf.

       The return values from ecvt() and fcvt() may point to static data which may be overwritten by  subsequent
       calls to these functions.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       The sprintf() function is preferred over this function.

RATIONALE

       None.

FUTURE DIRECTIONS

       These functions may be withdrawn in a future version.

SEE ALSO

       printf() , setlocale() , the Base Definitions volume of IEEE Std 1003.1-2001, <stdlib.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition,
       Standard  for  Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers,
       Inc and The Open Group. In the event of any discrepancy between this version and the  original  IEEE  and
       The  Open  Group  Standard,  the  original  IEEE and The Open Group Standard is the referee document. The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group                                   2003                                               ECVT(P)