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HP-UX 11i Version 3: February 2007

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fesetenv() — set floating-point environment


#include <fenv.h>

HP Integrity Server Only

int fesetenv(const fenv_t *envp);


void fesetenv(const fenv_t *envp);


The fesetenv() function establishes the floating-point environment represented by the object pointed to by envp. The argument envp must point to an object set by a call to fegetenv() or feholdexcept(), or equal the macro FE_DFL_ENV.

Note that fesetenv() merely installs the state of the floating-point exception flags represented through its argument, and does not raise these floating-point exceptions (hence no traps will be taken).


To use this function, compile either with the default -Ae option or with the -Aa and -D_HPUX_SOURCE options. Make sure your program includes <fenv.h>.

For Integrity servers, specify +Ofenvaccess on the compiler command line or place the call to this function under the effect of an affirmative FENV_ACCESS pragma:


If the FENV_ACCESS pragma is placed outside of any top-level declarations in a file, the pragma will apply to all declarations in the compilation following the pragma until another FENV_ACCESS pragma is encountered or until the end of the file is reached.

If the FENV_ACCESS pragma is placed at the beginning of a block (compound statement), the pragma will apply until another FENV_ACCESS pragma is encountered or until the end of the block is reached.

For PA-RISC, you might need to use the +Onomoveflops compiler option in order to prevent optimizations that can undermine the specified behavior of this function.

Link in the math library by specifying -lm on the compiler or linker command line.

For more information, see the HP-UX floating-point guide for HP Integrity servers at the following site: http://www.hp.com/go/fp.


Integrity Server Only

This function always returns 0, indicating that the environment was successfully established.




No errors are defined.


Store the current floating-point environment, continue on exceptions, and then restore the previous environment without raising the accumulated floating-point exceptions.

#include <fenv.h> /*...*/ fenv_t holdenv; feholdexcept(&holdenv); /* perform operations */ fesetenv(&holdenv);

Restore the default environment:

#include <fenv.h> /*...*/ fesetenv(FE_DFL_ENV);


fesetenv() : ISO/IEC C99 (including Annex F, "IEC 60559 floating-point arithmetic")

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