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				.\" $FreeBSD$
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				.Dd September 21, 2020
				.Dt DEVCTL_NOTIFY 9
				.Os
				.Sh NAME
				.Nm devctl_notify
				.Nd Send a message, via devctl, to userland
				.Sh SYNOPSIS
				.In sys/devctl.h
				.Ft void
				.Fn devctl_notify "const char system" "const char subsystem" "const char type" "const char data"
				.Sh DESCRIPTION
				Send a notification to user land via
				.Xr devctl 4 .
				See
				.Xr devctl 4
				for the format of these messages.
				.Pp
				The
				.Nm
				function creates a string using the following template:
				.Bd -literal
				snprintf(buffer, sizeof(buffer), "!system=%s subsystem=%s type=%s",
				system, subsystem, type);
				.Ed
				.Pp
				The
				.Vn system ,
				.Vn subsystem ,
				and
				.Vn type
				pointers cannot be NULL.
				.Pp
				The
				.Vn data
				argument may be NULL (for no additions) or a message formatted
				properly for
				.Xr devctl 4 .
				A space will be added to the above template and this argument copied
				verbatim to form the message passed to useland.
				bcrUnsubmitted Not Done Inline Actions s/useland/userland/ bcr: s/useland/userland/
				Senders should balance between only passing data that userland can't
				discover itself and sending all the data userland will want to use to
				decide what to do with the message.
				.Pp
				The current total message length limit is just under 1kb.
				Senders should try to remain well below this limit.
				.Sh SEE ALSO
				.Xr devctl 4
				.Xr devd 8
				.Sh AUTHORS
				This manual page was written by
				.An M. Warner Losh