__SETFPUCW(3)                       Linux Programmer's Manual                       __SETFPUCW(3)



NAME
       __setfpucw - set FPU control word on i386 architecture (obsolete)

SYNOPSIS
       #include <i386/fpu_control.h>

       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.

CONFORMING TO
       This function was a nonstandard GNU extension.

NOTES
       As  of  glibc 2.1 this function does not exist anymore.  There are new functions from C99,
       with prototypes in <fenv.h>, to control  FPU  rounding  modes,  like  fegetround(3),  fes‐
       etround(3),  and  the  floating-point environment, like fegetenv(3), feholdexcept(3), fes‐
       etenv(3), feupdateenv(3), and FPU exception handling, like feclearexcept(3),  fegetexcept‐
       flag(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.

EXAMPLE
       __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>

COLOPHON
       This page is part of release 3.74 of the Linux man-pages project.  A  description  of  the
       project,  information  about  reporting  bugs, and the latest version of this page, can be
       found at http://www.kernel.org/doc/man-pages/.



Linux                                       2012-12-31                              __SETFPUCW(3)