Index for Section 3

Alphabetical listing for A

atof(3)
NAME
  atof, strtod - Converts a character string to a double-precision floating-
  point value

LIBRARY
  Standard C Library (libc.a)

SYNOPSIS
  #include <stdlib.h>

  double atof(
      const char *nptr) ;

  double strtod(
      const char *nptr,
      char **endptr) ;

PARAMETERS
  nptr	    Points to the character string to convert.

  endptr    Specifies either a null value, or a pointer to the character that
	    ended the scan or to a null value.

DESCRIPTION
  The atof() function converts the string pointed to by the nptr parameter up
  to the first character that is inconsistent with the format of a floating-
  point number to a double floating-point value. Leading white-space
  characters are ignored.  A call to this function is equivalent to a call to
  strtod(nptr, (char **) NULL), except for error handling.  When the value
  cannot be represented, the result is undefined.

  The strtod() function converts the initial portion of the string pointed to
  by the nptr parameter to double representation.  First the input string is
  decomposed into the following three parts:

    ·  An initial, possibly empty, sequence of white-space characters (as
       specified by the isspace() function).

    ·  A subject sequence interpreted as a floating-point constant.

    ·  A final string of one or more unrecognized characters, including the
       terminating null character of the input string.

  After decomposition of the string, the subject sequence is converted to a
  floating-point number, and the resulting value is returned.  A subject
  sequence is defined as the longest initial subsequence of the input string,
  starting with the first nonwhite-space character, that is of the expected
  form. The expected form and order of the subject sequence is:

    ·  An optional plus (+) or minus (-) sign.

    ·  A  sequence of digits optionally containing a radix character.

    ·  An optional exponent part. An exponent part consists of e or E,
       followed by an optional sign, which is followed by one or more decimal
       digits.

  When the input string is empty or consists entirely of white space, or when
  the first nonwhite-space character is other than a sign, a digit, or a
  radix character, the subject sequence contains no characters.

  For the strtod() function, when the value of the endptr parameter is not
  (char**) NULL, a pointer to the character that terminated the scan is
  stored at *endptr.

  When a floating-point value cannot be formed, *endptr is set to nptr.

NOTES
  The setlocale() function may affect the radix character used in the
  conversion result.

  AES Support Level:
		 Full use

RETURN VALUES
  When the string is empty or begins with an unrecognized character, +0.0 is
  returned as the floating-point value.

  When a correct return value overflows, a properly signed HUGE_VAL (INF) is
  returned. On underflow, a properly signed 0 (zero) is returned.

  Upon successful completion, either function returns the converted
  floating-point value.

ERRORS
  If the atof() or strtod() function fails, errno may be set to the following
  value:

  [ERANGE]  The input string is out of range (that is, the subject sequence
	    can not be converted to a floating-point value without causing
	    underflow or overflow).

RELATED INFORMATION
  Functions: atoi(3), scanf(3)