feholdexcept()
QNX SDP8.0C Library ReferenceAPIDeveloper
Save the floating-point environment, clear all flags, and ignore future errors
Synopsis:
#include <fenv.h>
int feholdexcept( fenv_t *envp );
Arguments:
- envp
- A pointer to a fenv_t object where the function can store the environment.
Library:
- libm
- The general-purpose math library.
- libm-sve
- 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 feholdexcept() function saves the floating-point environment in the object that envp points to, clears all the floating-point status flags, and installs a nonstop mode. In nonstop mode, floating-point exceptions don't interrupt execution.
CAUTION:
This operation doesn't work on AArch64 targets.
There's a known hardware limitation that causes any saving of floating-point environments to be ignored.
To restore the floating-point environment, use fesetenv() or feupdateenv().
Returns:
0
Classification:
| Safety: | |
|---|---|
| Cancellation point | No |
| Signal handler | Yes |
| Thread | Yes |
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