NAME
fegetround() — get floating-point rounding direction mode
SYNOPSIS
#include <fenv.h>
int fegetround(void);
DESCRIPTION
The
fegetround()
function gets the current rounding direction, as specified by
the IEEE 754 (IEC 60559) floating-point standard.
The default rounding direction mode is round to nearest
(FE_TONEAREST).
USAGE
To use this function, compile either with the default
-Ae
option or with the
-Aa
and
-D_HPUX_SOURCE
options. Make sure your program includes
<fenv.h>.
For HP Integrity servers, specify
+Ofenvaccess
on the compiler command line or
place the call to this function under the effect of
an affirmative
FENV_ACCESS
pragma:
#pragma STDC FENV_ACCESS ON
If the
FENV_ACCESS
pragma is placed outside of any top-level
declarations in a file, the pragma will apply to all declarations in
the compilation following the pragma until another
FENV_ACCESS
pragma
is encountered or until the end of the file is reached.
If the
FENV_ACCESS
pragma is placed at the beginning of a block
(compound statement), the pragma will apply until another
FENV_ACCESS
pragma is encountered or until the end of the block is reached.
For PA-RISC, you might need to use the
+Onomoveflops
compiler option
in order to prevent optimizations that can undermine the specified behavior
of this function.
Link in the math library by specifying
-lm
on the compiler or linker command line.
For more information, see the
HP-UX floating-point guide for HP Integrity servers
at the following site:
http://www.hp.com/go/fp.
RETURN VALUE
The
fegetround()
function returns the value of the rounding direction macro
representing the current rounding direction.
The return value will match one of the following macros, which are
defined in
<fenv.h>:
- FE_TONEAREST
Round to nearest. If the two nearest representable are equally near,
the one with its least significant bit zero is delivered.
- FE_UPWARD
Round upwards (towards +infinity).
- FE_DOWNWARD
Round downwards (towards -infinity).
- FE_TOWARDZERO
Round toward zero.
ERRORS
No errors are defined.
EXAMPLES
Save, set, and restore the rounding direction.
#include <fenv.h>
/*...*/
{
int save_round;
save_round = fegetround();
fesetround(FE_UPWARD);
/*...*/
fesetround(save_round);
/*...*/
}
STANDARDS CONFORMANCE
fegetround()
: ISO/IEC C99 (including Annex F, ``IEC 60559 floating-point arithmetic'')
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