Index for Section 3

Alphabetical listing for E

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ecvt(3)
NAME
  ecvt, ecvt_r, fcvt, fcvt_r, gcvt - Convert a floating-point number to a
  string

SYNOPSIS
  #include <stdlib.h>

  char *ecvt(
	  double value,
	  int num_digits,
	  int *decimal_ptr,
	  int *sign );

  char *fcvt(
	  double value,
	  int num_digits,
	  int *decimal_ptr,
	  int *sign );

  char *gcvt(
	  double value,
	  int num_digits,
	  char *buffer );

  The following obsolete functions are supported in order to maintain
  backward compatibility with previous versions of the operating system. You
  should not use them in new designs.

  int ecvt_r(
	  double value,
	  int num_digits,
	  int *decimal_ptr,
	  int *sign,
	  char *buffer,
	  int len );

  int fcvt_r(
	  double value,
	  int num_digits,
	  int *decimal_ptr,
	  int *sign,
	  char *buffer,
	  int len );

LIBRARY
  Standard C Library (libc)

PARAMETERS
  value
      Specifies the double value to be converted.

  num_digits
      Specifies the number of digits in the resulting string.

  decimal_ptr
      Holds the position of the decimal point relative to the beginning of
      the string. A negative number means the decimal point is to the left of
      the digits given in the string.

  sign
      Holds a value of 0 (zero) if the value is positive or zero, and a
      nonzero value if it is negative.

  buffer
      Specifies the character array to be used as scratch space in
      calculations and for storing the resulting string.

  len Specifies the length of buffer. Because ecvt temporarily stores
      intermediate results of its calculations in the buffer, you must
      specify a len greater than 370. A value of 400 is recommended.

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

  The ecvt() function converts the value specified by the value parameter to
  a null-terminated string of length num_digits, and returns a pointer to it.
  The resulting low-order digit is rounded according to the current rounding
  mode. The decimal_ptr parameter is assigned to the position of the decimal
  point relative to the position of the string. The sign parameter is
  assigned a value of 0 (zero) if value is positive or zero, and a nonzero
  value if value is negative. The decimal point and sign are not included in
  the string.

  The fcvt() function is the same as the ecvt() function, except that it
  rounds to the correct digit for outputting num_digits of digits in C or
  FORTRAN F-format. In the F-format, num_digits is taken as the number of
  digits desired after the decimal point.

  The gcvt() function converts the value specified by the value parameter to
  a null-terminated string, stores it in the array pointed to by the buffer
  parameter, and then returns buffer. The gcvt() function attempts to produce
  a string of num_digits significant digits in FORTRAN F-format. If this is
  not possible, then E-format is used. The string is ready for printing,
  complete with minus sign, decimal point, or exponent, as appropriate.
  Trailing zeros are suppressed.

  In the F-format, num_digits is the number of digits desired after the
  decimal point. Very large numbers produce a very long string of digits
  before the decimal point, and then num_digits of digits after the decimal
  point. For large numbers, it is preferable to use the gcvt() or ecvt()
  function so that the E-format will be used.

  The ecvt(), fcvt(), and gcvt() functions represent the following special
  values that are specified in IEEE Standard 754-1985 for floating-point
  arithmetic according to the following table.

Index for Section 3

Alphabetical listing for E

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