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PdLockOffscreen()

Lock an offscreen context

Synopsis:

int PdLockOffscreen( PdOffscreenContext_t *osc,
                     PdOSCLockParams_t *params );

Arguments:

osc

A pointer to the PdOffscreenContext_t structure for the offscreen context. You must call PdCreateOffscreenLock() to create an offscreen lock for this context before you call PdLockOffscreen().

params

A pointer to a PdOSCLockParams_t structure (see below) that defines parameters for the lock. You can pass NULL for this argument.

Library:

ph

Description:

This function locks an offscreen context.

The PdOSCLockParams_t structure includes these members:

uint32_t flags

Flags, including:

• Pg_OSC_LOCK_TIMED_OUT -- blocking occurs only until the clock has gone past the value of the time_out member.

struct timespec *time_out

The absolute time at which to stop blocking if you've set Pg_OSC_LOCK_TIMED_OUT in the flags member. This behavior is like that of sem_timedwait().

Returns:

EOK

The context was succesfully locked.

Pg_OSC_LOCK_TIMED_OUT

Time out for lock occurred; the context wasn't locked.

Pg_OSC_LOCK_INVALID

The context lock is no longer valid (or never was in the first place i.e. it wasn't created with PdCreateOffscreenLock()).

Pg_OSC_LOCK_DEADLOCK

A deadlock condition was detected.

Classification:

Photon

Safety:
Interrupt handler	No
Signal handler	No
Thread	No

See also:

PdCreateOffscreenLock(), PdDestroyOffscreenLock(), PdGetOffscreenContextPtr(), PdIsOffscreenLocked(), PdUnlockOffscreen()

"Offscreen locks" in the Raw Drawing and Animation chapter of the Photon Programmer's Guide

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