fpgetmask(3)
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FPGETMASK(3) NetBSD Library Functions Manual FPGETMASK(3)
NAME
fpgetmask, fpgetround, fpgetsticky, fpsetmask, fpsetround, fpsetsticky --
IEEE FP mode control
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <ieeefp.h>
fp_except
fpgetmask(void);
fp_rnd
fpgetround(void);
fp_except
fpgetsticky(void);
fp_except
fpsetmask(fp_except mask);
fp_rnd
fpsetround(fp_rnd rnd_dir);
fp_except
fpsetsticky(fp_except sticky);
DESCRIPTION
A rounding mode is one of FP_RZ, FP_RM, FP_RN, or FP_RP, for rounding
towards zero, rounding (Minus infinity) down, rounding to nearest, and
rounding (Plus infinity) up. The default mode is FP_RN.
An fp_except value is a bitmask specifying an exception type and contain-
ing any of the values listed below.
FP_X_INV Invalid Operation
FP_X_DZ Division by zero
FP_X_OFL Overflow
FP_X_UFL Underflow
FP_X_IMP Imprecision (inexact)
FP_X_IOV Integer Overflow
The fpsetmask() function will set the current exception mask, i.e., it
will cause future operations with the specified result status to raise
the SIGFPE exception. The fpgetmask() function will return the current
exception mask.
The fpsetround() function will cause future operations to use the speci-
fied dynamic rounding mode. The fpgetround() function will return the
current rounding mode.
Note: On some architectures, instructions can optionally specify static
rounding modes and exception enables that will supersede the
specified dynamic mode. On other architectures, these features
may not be fully supported.
A ``sticky'' status word may be maintained in which a bit is set every
time an exceptional floating point condition is encountered, whether or
not a SIGFPE is generated. The fpsetsticky() function will set or clear
the specified exception history bits. The fpgetsticky() function will
return the exception history bits.
RETURN VALUES
The fpgetround() and fpsetround() functions return the (previous) round-
ing mode. The fpgetmask(), fpsetmask(), fpgetsticky(), and fpsetsticky()
functions return the (previous) exception mask and exception history
bits.
SEE ALSO
sigaction(2)
NetBSD 5.0 April 4, 2004 NetBSD 5.0
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