c/numeric/fenv/feexceptflag

1) Attempts to obtain the full contents of the floating-point exception flags that are listed in the bitmask argument, which is a bitwise OR of the floating-point exception macros.

2) Attempts to copy the full contents of the floating-point exception flags that are listed in from  into the floating-point environment. Does not raise any exceptions, only modifies the flags.

The full contents of a floating-point exception flag is not necessarily a boolean value indicating whether the exception is raised or cleared. For example, it may be a struct which includes the boolean status and the address of the code that triggered the exception. These functions obtain all such content and obtain/store it in in implementation-defined format.

Return value
on success, non-zero otherwise.