PgShmemCreate()

Create a block of shared memory

Synopsis:

void *PgShmemCreate( unsigned long size,
                     char const *name );

Library:

ph

Description:

This function creates a block of shared memory. The size argument determines the size of the block.

If you pass name as NULL, this function generates a unique name in the form Pg########; this is the preferred mode of operation. If you pass a name, make sure that it isn't already in use.

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You must use the “mx” form of a draw function to pass the shared memory reference. Otherwise, the data is copied into the draw event.

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The Photon library uses atexit() to arrange for PgShmemCleanup() to be called when your program terminates normally. If your program terminates abnormally, it should call PgShmemCleanup() explicitly.

Returns:

A local pointer to shared memory. If an error occurs, it returns NULL and sets errno.

Errors:

See the errors for shm_open() in the QNX Neutrino Library Reference.

Classification:

Photon

See also:

PgDrawBitmapmx(), PgDrawImagemx(), PgShmemAttach(), PgShmemCleanup(), PgShmemDestroy(), PgShmemDetach()

shm_open() in the QNX Neutrino Library Reference