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Standard C Library Functionsdecimal_to_floating(3C)


NAME

 decimal_to_floating, decimal_to_single, decimal_to_double, decimal_to_extended, decimal_to_quadruple - convert decimal record to floating-point value

SYNOPSIS

 
#include <floatingpoint.h>
void decimal_to_single(single *px, decimal_mode *pm, decimal_record *pd, fp_exception_field_type *ps);
 void decimal_to_double(double *px, decimal_mode *pm, decimal_record *pd, fp_exception_field_type *ps);
 void decimal_to_extended(extended *px, decimal_mode *pm, decimal_record *pd, fp_exception_field_type *ps);
 void decimal_to_quadruple(quadruple *px, decimal_mode *pm, decimal_record *pd, fp_exception_field_type *ps);

DESCRIPTION

 

The decimal_to_floating() functions convert the decimal record at *pd into a floating-point value at *px, observing the modes specified in *pm and setting exceptions in *ps. If there are no IEEE exceptions, *ps will be zero.

pd->sign and pd->fpclass are always taken into account. pd->exponent, pd->ds and pd->ndigits are used when pd->fpclass is fp_normal or fp_subnormal. In these cases pd->ds must contain one or more ascii digits followed by a NULL and pd->ndigits is assumed to be the length of the string pd->ds. Notice that for efficiency reasons, the assumption that pd->ndigits == strlen(pd->ds) is NEVER verified.

On output, *px is set to a correctly rounded approximation to

(pd->sign)*(pd->ds)*10**(pd->exponent)

Thus if pd->exponent == -2 and pd->ds == "1234", *px will get 12.34 rounded to storage precision. pd->ds cannot have more than DECIMAL_STRING_LENGTH-1 significant digits because one character is used to terminate the string with a NULL. If pd->more != 0 on input then additional nonzero digits follow those in pd->ds; fp_inexact is set accordingly on output in *ps.

*px is correctly rounded according to the IEEE rounding modes in pm->rd. *ps is set to contain fp_inexact, fp_underflow, or fp_overflow if any of these arise.

pm->df and pm->ndigits are not used.

strtod(3C), scanf(3C), fscanf(3C), and sscanf(3C) all use decimal_to_double().

ATTRIBUTES

 

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPEATTRIBUTE VALUE
MT-LevelMT-Safe

SEE ALSO

 

fscanf(3C), scanf(3C), sscanf(3C), strtod(3C), attributes(5)


SunOS 5.9Go To TopLast Changed 29 Dec 1996

 
      
      
Copyright 2002 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.