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 argu-
ment 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(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
|MT-Level |MT-Safe |
+-----------------------------+-----------------------------+
SEE ALSO
feholdexcept(3M), fenv.h(3HEAD), feupdateenv(3M), attributes(5), standards(5)
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 sta-
tus 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 12 Jul 2006 fegetenv(3M)