Manual Pages for UNIX Operating System command usage for man fesetenv

Mathematical Library Functions                       fegetenv(3M)



NAME
     fegetenv, fesetenv -  get  and  set  current  floating-point
     environment

SYNOPSIS
     c99 [ flag... ] file... -lm [ library... ]
     #include 

     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(5) for descriptions of the  following  attri-
     butes:













SunOS 5.11          Last change: 12 Jul 2006                    1






Mathematical Library Functions                       fegetenv(3M)



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|
    | Standard                    | See standards(5).           |
    |_____________________________|_____________________________|


SEE ALSO
     feholdexcept(3M),  fenv.h(3HEAD),  feupdateenv(3M),   attri-
     butes(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 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 result-
     ing behavior is not defined.


     As described in fex_set_handling(3M), when a handling  func-
     tion  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          Last change: 12 Jul 2006                    2