__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 (floating-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 control FPU rounding modes, like fegetround(3), fesetround(3), and the floating-point environment, like fegetenv(3), feholdexcept(3), fesetenv(3), feupdateenv(3), and FPU exception handling, like feclearexcept(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>