NAME
fesetround() — set floating-point rounding direction mode
SYNOPSIS
#include <fenv.h>
int fesetround(int round);
DESCRIPTION
The
fesetround()
function establishes the rounding direction represented by
its argument
round.
The
round
argument must equal one of the macros:
FE_TONEAREST,
FE_UPWARD,
FE_DOWNWARD,
and
FE_TOWARDZERO.
If the argument does not match a rounding direction macro, the
rounding direction is not changed.
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
fesetround()
function returns a zero value if and only if the argument is equal to a
rounding direction macro.
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
fesetround()
: ISO/IEC C99 (including Annex F, "IEC 60559 floating-point arithmetic")
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