IEEE_EXCEPTIONS

Index

NAME

USAGE

SYNOPSIS

DERIVED-TYPE DESCRIPTION

PARAMETER DESCRIPTION

PROCEDURE DESCRIPTION

SEE ALSO

BUGS

NAME

USAGE

This module provides types, parameters and procedures for using IEEE exception flags. Its contents conform to technical report ISO/IEC TR 15580:1998(E).  

SYNOPSIS

Derived Types

IEEE_FLAG_TYPE, IEEE_STATUS_TYPE.

Parameters

IEEE_ALL, IEEE_DIVIDE_BY_ZERO, IEEE_INEXACT, IEEE_INVALID, IEEE_OVERFLOW, IEEE_UNDERFLOW, IEEE_USUAL.

Procedures

IEEE_GET_FLAG, IEEE_GET_HALTING_MODE, IEEE_GET_STATUS, IEEE_SET_FLAG, IEEE_SET_HALTING_MODE, IEEE_SET_STATUS, IEEE_SUPPORT_FLAG, IEEE_SUPPORT_HALTING.

DERIVED-TYPE DESCRIPTION

This type is provided for the purpose of specifying IEEE exception flags; a value of this type indicates each particular flag.

TYPE IEEE_STATUS_TYPE
      PRIVATE
      ...
END TYPE

This type is provided to allow the user to save (and restore) the current floating-point status. The floating-point status includes the state (quiet or signalling) of each IEEE exception flag, and the current rounding mode.

PARAMETER DESCRIPTION

Array specifying all IEEE exception flags.

TYPE(IEEE_FLAG_TYPE),PARAMETER :: IEEE_DIVIDE_BY_ZERO

Specifies the division-by-zero exception flag.

TYPE(IEEE_FLAG_TYPE),PARAMETER :: IEEE_INEXACT

Specifies the inexact exception flag.

TYPE(IEEE_FLAG_TYPE),PARAMETER :: IEEE_INVALID

Specifies the invalid exception flag.

TYPE(IEEE_FLAG_TYPE),PARAMETER :: IEEE_OVERFLOW

Specifies the overflow exception flag.

TYPE(IEEE_FLAG_TYPE),PARAMETER :: IEEE_UNDERFLOW

Specifies the underflow exception flag.

TYPE(IEEE_FLAG_TYPE),PARAMETER :: IEEE_USUAL = &
      (/ IEEE_OVERFLOW,IEEE_DIVIDE_BY_ZERO,IEEE_INVALID /)

Array specifying the most commonly desired subset of exception flags.

PROCEDURE DESCRIPTION

Sets FLAG_VALUE to .TRUE. if the specified IEEE exception flag is signalling, and to .FALSE. otherwise.

ELEMENTAL SUBROUTINE IEEE_GET_HALTING_MODE(FLAG,HALTING_MODE)
TYPE(IEEE_FLAG_TYPE),INTENT(IN) :: FLAG
LOGICAL,INTENT(OUT) :: HALTING_MODE

Sets HALTING_MODE to .TRUE. if an occurrence of the specified exception will cause program termination, and to .FALSE. otherwise.

SUBROUTINE IEEE_GET_STATUS(STATUS_VALUE)
TYPE(IEEE_STATUS_TYPE),INTENT(OUT) :: STATUS_VALUE

Stores the current floating-point status in STATUS_VALUE.

ELEMENTAL SUBROUTINE IEEE_SET_FLAG(FLAG,FLAG_VALUE)
TYPE(IEEE_FLAG_TYPE),INTENT(IN) :: FLAG
LOGICAL,INTENT(IN) :: INTENT(IN) :: FLAG_VALUE

Sets the specified exception flag to signalling if FLAG_VALUE is .TRUE., and to quiet otherwise.

ELEMENTAL SUBROUTINE IEEE_SET_HALTING_MODE(FLAG,HALTING_MODE)
TYPE(IEEE_FLAG_TYPE),INTENT(IN) :: FLAG
LOGICAL,INTENT(IN) :: HALTING_MODE

Sets the halting mode for exception FLAG to true if HALTING_MODE is .TRUE., and to false otherwise. If the halting mode for an exception is true, an occurrence of that exception will cause program termination.

SUBROUTINE IEEE_SET_STATUS(STATUS_VALUE)
TYPE(IEEE_STATUS_TYPE),INTENT(IN) :: STATUS_VALUE

Restores the current floating-point status to that saved by a preceding invocation of IEEE_GET_STATUS.

LOGICAL FUNCTION IEEE_SUPPORT_FLAG(FLAG,X)
TYPE(IEEE_FLAG_TYPE),INTENT(IN) :: FLAG
REAL(any kind),OPTIONAL :: X

Returns .TRUE. if detection of the specified exception is supported; either for all real kinds (if X is absent), or for reals of the same kind as X.

LOGICAL FUNCTION IEEE_SUPPORT_HALTING(FLAG)
TYPE(IEEE_FLAG_TYPE),INTENT(IN) :: FLAG

Returns .TRUE. if IEEE_SET_HALTING can be used to alter the halting mode of the specified exception, for all real kinds for which IEEE_SUPPORT_FLAG returns .TRUE..

SEE ALSO

BUGS

© The Numerical Algorithms Group Ltd, Oxford UK. 2001