On 8/16/2025 10:03 PM, Eli Zaretskii wrote:
> Calls to CHECK_* should be made by the primitive itself, not by its
> subroutine.  This is to allow the subroutines to be called where such
> tests were already done, or are inappropriate.  The idea is that only
> stuff exposed to Lisp validates the Lisp objects passed as arguments.

Good to know, thanks.

> P.S. I'd like to see what this does on Windows, where there's neither
> SIGPIPE nor EPIPE, but that's a separate funeral.

For what it's worth, Gnulib says the following:

/* On native Windows platforms, SIGPIPE does not exist.  When write() is
    called on a pipe with no readers, WriteFile() fails with error
    GetLastError() = ERROR_NO_DATA, and write() in consequence fails with
    error EINVAL.  */

Gnulib's 'write' (well really, 'rpl_write') checks for ERROR_NO_DATA and 
raises SIGPIPE for us, so hopefully we're ok here?