MirOS Manual: powerhook_disestablish(9), powerhook_establish(9)

POWERHOOK_ESTABLISH(9)        BSD Kernel Manual         POWERHOOK_ESTABLISH(9)

NAME

     powerhook_establish, powerhook_disestablish - add or remove a power hook

SYNOPSIS

     #include <sys/types.h>
     #include <sys/systm.h>

     void *
     powerhook_establish(void (*fn)(int, void *), void *arg);

     void
     powerhook_disestablish(void *cookie);

DESCRIPTION

     The powerhook_establish() function adds fn to the list of hooks invoked
     by dopowerhooks(9) during any change in apm(4) power state (i.e., during
     a "suspend", "standby", or "resume"). When invoked, the hook function fn
     will be passed an int why and arg as its arguments. The int value why
     will be one of PWR_RESUME, PWR_SUSPEND, and PWR_STANDBY.

     The powerhook_disestablish() function removes the hook described by the
     opaque pointer cookie from the list of power hooks. If cookie is invalid,
     the result of powerhook_disestablish() is undefined.

RETURN VALUES

     If successful, powerhook_establish() returns an opaque pointer describing
     the newly established power hook. Otherwise, it returns NULL.

EXAMPLES

     It may be appropriate to use a power hook to disestablish interrupts and
     disable PCMCIA functions on PC Cards that are present when the system is
     put into suspend mode. The reverse should happen on resume.

     It may be appropriate to use a power hook to halt audio output in a sound
     driver at suspend-time. On resume, it may not be possible to recover au-
     dio output, but at least the device can be put into a known, working
     state.

SEE ALSO

     apm(4), dopowerhooks(9)

MirOS BSD #10-current            July 1, 2000                                1

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