ado_shm_alloc()

Allocate shared memory

Synopsis:

#include <audio_driver.h>

void *ado_shm_alloc( size_t size,
                     char *name,
                     int32_t flags,
                     off64_t *phys_addr );

Arguments:

size

The size of the block to allocate, in bytes.

name

The name of the shared region. The storage requirements for name are defined as QNX_SHM_NAME_LEN.

flags

Restrictions on the memory region; any combination of:

• ADO_SHM_DMA_SAFE — the region must be physical to allow DMA operations.
• ADO_DMA_ISA — the region must begin on a 64-kilobyte boundary.
• ADO_DMA_16M — the region must be allocated within the first 16M of memory.

phys_addr

A pointer to where ado_shm_alloc() should store the physical address of the region.

Description:

The ado_shm_alloc() function allocates a block of shared memory. You use it mostly for the DMA buffer so that it can be shared.

The ado_shm_mmap() function is for cards where the DMA buffer is in onboard memory; it mmaps the card memory and makes the region shared without allocating it.

Returns:

A pointer to the allocated memory, or NULL if an error occurred (errno is set).

Classification:

QNX Neutrino

See also:

ado_shm_free(), ado_shm_mmap()