#### 24.10.1 BSD Function to Establish a Handler

— Data Type: struct sigvec

> This data type is the BSD equivalent of `struct sigaction` (see Advanced Signal Handling); it is used to specify signal actions to the `sigvec` function. It contains the following members:

> `sighandler_t sv_handler`
>   This is the handler function.
> `int sv_mask`
>   This is the mask of additional signals to be blocked while the handler function is being called.
> `int sv_flags`
>   This is a bit mask used to specify various flags which affect the behavior of the signal. You can also refer to this field as `sv_onstack`.

These symbolic constants can be used to provide values for the `sv_flags` field of a `sigvec` structure. This field is a bit mask value, so you bitwise-OR the flags of interest to you together.

— Macro: int SV_ONSTACK

> If this bit is set in the `sv_flags` field of a `sigvec` structure, it means to use the signal stack when delivering the signal.

— Macro: int SV_INTERRUPT

> If this bit is set in the `sv_flags` field of a `sigvec` structure, it means that system calls interrupted by this kind of signal should not be restarted if the handler returns; instead, the system calls should return with a `EINTR` error status. See Interrupted Primitives.

— Macro: int SV_RESETHAND

> If this bit is set in the `sv_flags` field of a `sigvec` structure, it means to reset the action for the signal back to `SIG_DFL` when the signal is received.

— Function: int sigvec (int signum, const struct sigvec *action, struct sigvec *old-action)

> Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

> This function is the equivalent of `sigaction` (see Advanced Signal Handling); it installs the action action for the signal signum, returning information about the previous action in effect for that signal in old-action.

— Function: int siginterrupt (int signum, int failflag)

> Preliminary: | MT-Unsafe const:sigintr | AS-Unsafe | AC-Unsafe corrupt | See POSIX Safety Concepts.

> This function specifies which approach to use when certain primitives are interrupted by handling signal signum. If failflag is false, signal signum restarts primitives. If failflag is true, handling signum causes these primitives to fail with error code `EINTR`. See Interrupted Primitives.