Set the current floating-point environment
Synopsis:
#include <fenv.h>
int fesetenv( const fenv_t *envp );
Arguments:
- envp
- A pointer to a fenv_t object where the function can copy the environment from.
You must have obtained this value from a previous call to
feholdexcept()
or
fegetenv(),
or be FE_DFL_ENV, which points to a full copy of the default floating-point environment
(i.e., the environment as loaded at program startup).
Library:
- libm
- The general-purpose math library.
- libm-sve
- (QNX Neutrino 7.1 or later)
A library that optimizes the code for ARMv8.2 chips that have Scalable Vector Extension hardware.
Your system requirements will determine how you should work with these libraries:
- If you want only selected processes to run with the SVE version, you can include both libraries in your OS image
and use the -l m or -l m-sve option to
qcc
to link explicitly against the appropriate one.
- If you want all processes to use the SVE version, include libm-sve.so in your OS image
and set up a symbolic link from libm.so to libm-sve.so.
Use the -l m option to
qcc
to link against the library.
Note:
Compile your program with the -fno-builtin option to prevent the compiler from using a
built-in version of the function.
Description:
The fesetenv() function sets the current floating-point environment from the object that
envp points to.
If any of the floating-point status flags are set in envp, they're set in the environment
(and you can then use
fetestexcept()
to test for them), but the corresponding floating-point exceptions aren't raised.
Classification:
C99,
POSIX 1003.1
Safety: |
|
Cancellation point |
No |
Interrupt handler |
Yes |
Signal handler |
Yes |
Thread |
Yes |