FEGETENV(3M) Mathematical Library Functions FEGETENV(3M)
NAME
fegetenv, fesetenv - get and set current floating-point environment
SYNOPSIS
c99 [
flag... ]
file...
-lm [
library... ]
#include <fenv.h>
int fegetenv(
fenv_t *envp);
int fesetenv(
const fenv_t *envp);
DESCRIPTION
The
fegetenv() function attempts to store the current floating-point
environment in the object pointed to by
envp.
The
fesetenv() function attempts to establish the floating-point
environment represented by the object pointed to by
envp. The
envp argument points to an object set by a call to
fegetenv() or
feholdexcept(3M), or equals a floating-point environment macro. The
fesetenv() function does not raise floating-point exceptions, but
only installs the state of the floating-point status flags
represented through its argument.
RETURN VALUES
If the representation was successfully stored, fegetenv returns 0.
Otherwise, it returns a non-zero value.
If the environment was successfully established, fesetenv returns 0.
Otherwise, it returns a non-zero value.
ERRORS
No errors are defined.
ATTRIBUTES
See
attributes(7) for descriptions of the following attributes:
+----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+----------------------------+-----------------------------+
|Interface Stability | Standard |
+----------------------------+-----------------------------+
|MT-Level | MT-Safe |
+----------------------------+-----------------------------+
SEE ALSO
fenv.h(3HEAD),
feholdexcept(3M),
feupdateenv(3M),
attributes(7),
standards(7)NOTES
In a multithreaded program, the
fegetenv() and
fegetenv() functions
affect the floating point environment only for the calling thread.
These functions automatically install and deinstall
SIGFPE handlers
and set and clear the trap enable mode bits in the floating point
status register as needed. If a program uses these functions and
attempts to install a
SIGFPE handler or control the trap enable mode
bits independently, the resulting behavior is not defined.
As described in
fex_set_handling(3M), when a handling function
installed in
FEX_CUSTOM mode is invoked, all exception traps are
disabled (and will not be reenabled while
SIGFPE is blocked). Thus,
attempting to change the environment from within a handler by calling
fesetenv or
feupdateenv(3M) might not produce the expected results.
SunOS 5.11 July 12, 2006 FEGETENV(3M)
