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                                                               strtod(3C)



        _________________________________________________________________
        strtod
        Convert a string to a double-precision floating-point number.
        _________________________________________________________________


        Calling Sequence

        double strtod();
        double x;
        char *str, **ptr;
        x = strtod(str, ptr);


        Description

        Use the strtod function to convert an ASCII string into a
        double-precision floating-point number.  The strtod function
        recognizes the following values:

        *    An optional string of whitespace characters.

        *    An optional sign ( + or - ).

        *    A string of digits with an optional decimal point.

        *    An optional E or e, followed by an optional sign or space,
             followed by an integer exponent.  Conversion stops when
             strtod encounters an invalid character.

        The include file dg_stdio.h defines this function.


        Returns

        If the value of ptr is not (char **)NULL, strtod returns a
        pointer to the character that terminates the scan.  It returns
        this pointer to the location that ptr points to.

        If the floating-point value would cause overflow, strtod returns
        +HUGE (depending on the sign of the value), and sets errno to
        ERANGE.  If the value would cause floating-point underflow,
        strtod returns zero and sets errno to ERANGE.


        Related Functions

        See also the atof, sscanf, and strtol functions.






        DG/UX 4.00                                                 Page 1
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