FLOATINGPOINT(3)

NAME
floatingpoint - IEEE floating point definitions

SYNOPSIS
#include <sys/ieeefp.h>
#include <floatingpoint.h>

DESCRIPTION
This file defines constants, types, variables, and functions used to implement standard floating point according to ANSI/IEEE Std 754-1985. The variables and functions are implemented in libc.a. The included file <sys/ieeefp.h> defines certain types of interest to the kernel.

IEEE Rounding Modes:

fp_direction_type
    The type of the IEEE rounding direction mode. Note: the order of enumeration varies according to hardware.

fp_direction
    The IEEE rounding direction mode currently in force. This is a global variable that is intended to reflect the hardware state, so it should only be written indirectly through a function like ieee_flags ("set","direction",...) that also sets the hardware state.

fp_precision_type
    The type of the IEEE rounding precision mode, which only applies on systems that support extended precision such as Sun-3 systems with 68881's.

fp_precision
    The IEEE rounding precision mode currently in force. This is a global variable that is intended to reflect the hardware state on systems with extended precision, so it should only be written indirectly through a function like ieee_flags("set","precision",...).

SIGFPE handling:

sigfpe_code_type
    The type of a SIGFPE code.

sigfpe_handler_type
    The type of a user-definable SIGFPE exception handler called to handle a particular SIGFPE code.

SIGFPE_DEFAULT
    A macro indicating the default SIGFPE exception handling, namely to perform the exception handling specified by calls to ieee_handler(3M), if any, and otherwise to dump core using abort(3).

SIGFPE_IGNORE
    A macro indicating an alternate SIGFPE exception handling, namely to ignore and continue execution.

SIGFPE_ABORT
    A macro indicating an alternate SIGFPE exception handling, namely to abort with a core dump.

IEEE Exception Handling:

N_IEEE_EXCEPTION
    The number of distinct IEEE floating-point exceptions.

fp_exception_type
    The type of the N_IEEE_EXCEPTION exceptions. Each exception is given a bit number.

fp_exception_field_type
    The type intended to hold at least N_IEEE_EXCEPTION bits corresponding to the IEEE exceptions numbered by fp_exception_type. Thus fp_inexact corresponds to the least significant bit and fp_invalid to the fifth least significant bit. Note: some operations may set more than one exception.

fp_accrued_exceptions
    The IEEE exceptions between the time this global variable was last cleared, and the last time a function like ieee_flags("get","exception",...) was called to update the variable by obtaining the hardware state.

ieee_handlers
    An array of user-specifiable signal handlers for use by the standard SIGFPE handler for IEEE arithmetic-related SIGFPE codes. Since IEEE trapping modes correspond to hardware modes, elements of this array should only be modified with a function like ieee_handler(3M) that performs the appropriate hardware mode update. If no sigfpe_handler has been declared for a particular IEEE-related SIGFPE code, then the related ieee_handlers will be invoked.

IEEE Formats and Classification:

single;extended
    Definitions of IEEE formats.

fp_class_type
    An enumeration of the various classes of IEEE values and symbols.

IEEE Base Conversion:

    The functions described under floating_to_decimal(3) and decimal_to_floating(3) not only satisfy the IEEE Standard, but also the stricter requirements of correct rounding for all arguments.

DECIMAL_STRING_LENGTH
    The length of a decimal_string.

decimal_string
    The digit buffer in a decimal_record.

decimal_record
    The canonical form for representing an unpacked decimal floating-point number.

decimal_form
    The type used to specify fixed or floating binary to decimal conversion.

decimal_mode
    A struct that contains specifications for conversion between binary and decimal.

decimal_string_form
    An enumeration of possible valid character strings representing floating-point numbers, infinities, or NaNs.

SEE ALSO
abort(3), decimal_to_floating(3), econvert(3), floating_to_decimal(3), ieee_flags(3M), ieee_handler(3M), sigfpe(3), string_to_decimal(3), strtod(3)