man3p/fegetround.3p

   1 .\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
   2 .TH "FEGETROUND" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
   3 .\" fegetround
   4 .SH NAME
   5 fegetround, fesetround \- get and set current rounding direction
   6 .SH SYNOPSIS
   7 .LP
   8 \fB#include <fenv.h>
   9 .br
  10 .sp
  11 int fegetround(void);
  12 .br
  13 int fesetround(int\fP \fIround\fP\fB);
  14 .br
  15 \fP
  16 .SH DESCRIPTION
  17 .LP
  18 The \fIfegetround\fP() function shall get the current rounding direction.
  19 .LP
  20 The \fIfesetround\fP() function shall establish the rounding direction
  21 represented by its argument \fIround\fP. If the
  22 argument is not equal to the value of a rounding direction macro,
  23 the rounding direction is not changed.
  24 .SH RETURN VALUE
  25 .LP
  26 The \fIfegetround\fP() function shall return the value of the rounding
  27 direction macro representing the current rounding
  28 direction or a negative value if there is no such rounding direction
  29 macro or the current rounding direction is not
  30 determinable.
  31 .LP
  32 The \fIfesetround\fP() function shall return a zero value if and only
  33 if the requested rounding direction was established.
  34 .SH ERRORS
  35 .LP
  36 No errors are defined.
  37 .LP
  38 \fIThe following sections are informative.\fP
  39 .SH EXAMPLES
  40 .LP
  41 The following example saves, sets, and restores the rounding direction,
  42 reporting an error and aborting if setting the rounding
  43 direction fails:
  44 .sp
  45 .RS
  46 .nf
  47
  48 \fB#include <fenv.h>
  49 #include <assert.h>
  50 void f(int round_dir)
  51 {
  52     #pragma STDC FENV_ACCESS ON
  53     int save_round;
  54     int setround_ok;
  55     save_round = fegetround();
  56     setround_ok = fesetround(round_dir);
  57     assert(setround_ok == 0);
  58     /* ... */
  59     fesetround(save_round);
  60     /* ... */
  61 }
  62 \fP
  63 .fi
  64 .RE
  65 .SH APPLICATION USAGE
  66 .LP
  67 None.
  68 .SH RATIONALE
  69 .LP
  70 None.
  71 .SH FUTURE DIRECTIONS
  72 .LP
  73 None.
  74 .SH SEE ALSO
  75 .LP
  76 The Base Definitions volume of IEEE\ Std\ 1003.1-2001, \fI<fenv.h>\fP
  77 .SH COPYRIGHT
  78 Portions of this text are reprinted and reproduced in electronic form
  79 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
  80 -- Portable Operating System Interface (POSIX), The Open Group Base
  81 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
  82 Electrical and Electronics Engineers, Inc and The Open Group. In the
  83 event of any discrepancy between this version and the original IEEE and
  84 The Open Group Standard, the original IEEE and The Open Group Standard
  85 is the referee document. The original Standard can be obtained online at
  86 http://www.opengroup.org/unix/online.html .