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fegetenv(3m) [opensolaris man page]

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)

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FEGETENV(3)						   BSD Library Functions Manual 					       FEGETENV(3)

NAME
fegetenv, feholdexcept, fesetenv, feupdateenv -- functions providing access to the floating-point environment. SYNOPSIS
#include <fenv.h> #pragma STDC FENV_ACCESS ON int fegetenv(fenv_t *envp); int feholdexcept(fenvt_t *envp); int fesetenv(fenv_t *envp); int feupdateenv(fenv_t *envp); DESCRIPTION
These functions provide the means to manage the entire floating-point environment--including both status flags and control modes--as a single entity. The fegetenv() function attempts to store the current floating-point environment in the object pointed to by envp. It returns zero if the environment was successfully stored, and a nonzero value otherwise. The feholdexcept() function saves the current floating-point environment in the object pointed to by envp, clears the floating-point status flags, and then installs a "non-stop" mode, if available, under which no traps are taken for floating-point exceptions (as is the case in default IEEE-754 floating-point execution). It returns zero if and only if such a mode was successfully installed. The fesetenv() function attempts to establish the floating-point environment represented by the object pointed to by envp. This object shall have been set by a call to fegetenv() or feholdexcept(), or be equal to a floating-point environment macro defined in <fenv.h>. Note that this function merely installs the floating-point status flags represented by its argument, and does not raise the corresponding floating- point exceptions. It returns zero if and only if the environment pointed to by envp was successfully installed. The feupdateenv() function attempts to save the currently raised floating-point flags, install the floating-point environment represented by *envp, and then raise the floating-point exceptions corresponding to the saved flags. The object pointed to by envp shall have been set by a call to fegetenv() or feholdexcept(), or be equal to a floating-point environment macro defined in <fenv.h>. It returns zero if and only if all of the specified actions were successfully carried out. SEE ALSO
fenv(3), feclearexcept(3), fegetexceptflag(3), fegetround(3), feraiseexcept(3), fesetexceptflag(3), fesetround(3), feraiseexcept(3) STANDARDS
These functions conform to ISO/IEC 9899:TC3. BSD
May 9, 2011 BSD
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