Re: SIGCHLD in vfork child context

[Paul Eggert]

YAMAMOTO Mitsuharu wrote:
> It seems that calling waitpid from the SIGCHLD handler results in
> ECHILD in the vfork child context

Why is the vfork child process getting a SIGCHLD signal? That process doesn't 
have any children. Is the macOS kernel simply buggy? If so, I suggest adding a 
short explanation of the situation to this comment:

> +    /* Call the SIGCHLD handler in case we have received SIGCHLD in
> +       the vfork child context.  The signal mask is restored by
> +       unblock_child_signal below.  */

If not, then I don't understand the situation....

> +    (*action.sa_handler) (SIGCHLD);

No need for the * and the first set of parens. I.e., this is OK:

    action.sa_handler (SIGCHLD);

Otherwise, looks OK; thanks.