__setfpucw(3) Library Functions Manual __setfpucw(3)
NAME
__setfpucw - set FPU control word on i386 architecture (obsolete)
LIBRARY
Standard C library (libc, -lc)
SYNOPSIS
#include <i386/fpu_control.h>
[[deprecated]] void __setfpucw(unsigned short control_word);
DESCRIPTION
__setfpucw() transfers control_word to the registers of the FPU (float-
ing-point unit) on the i386 architecture. This was used to control
floating-point precision, rounding and floating-point exceptions.
STANDARDS
GNU.
HISTORY
Removed in glibc 2.1.
NOTES
There are new functions from C99, with prototypes in <fenv.h>, to con-
trol FPU rounding modes, like fegetround(3), fesetround(3), and the
floating-point environment, like fegetenv(3), feholdexcept(3), fes-
etenv(3), feupdateenv(3), and FPU exception handling, like feclearex-
cept(3), fegetexceptflag(3), feraiseexcept(3), fesetexceptflag(3), and
fetestexcept(3).
If direct access to the FPU control word is still needed, the _FPU_GETCW
and _FPU_SETCW macros from <fpu_control.h> can be used.
EXAMPLES
__setfpucw(0x1372)
Set FPU control word on the i386 architecture to
• extended precision
• rounding to nearest
• exceptions on overflow, zero divide and NaN
SEE ALSO
feclearexcept(3)
<fpu_control.h>
Linux man-pages 6.9.1 2024-05-02 __setfpucw(3)
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