# /builddir/build/BUILD/alsa-lib-1.1.0/src/pcm/pcm_hw.c File Reference

PCM HW Plugin Interface. More...

## Enumerations

enum | { CHMAP_CTL_QUERY, CHMAP_CTL_GET, CHMAP_CTL_SET }

## Functions

snd_pcm_chmap_query_t ** | snd_pcm_query_chmaps_from_hw (int card, int dev, int subdev, snd_pcm_stream_t stream)
int | snd_pcm_hw_open_fd (snd_pcm_t **pcmp, const char *name, int fd, int mmap_emulation, int sync_ptr_ioctl)
| Creates a new hw PCM.
int | snd_pcm_hw_open (snd_pcm_t **pcmp, const char *name, int card, int device, int subdevice, snd_pcm_stream_t stream, int mode, int mmap_emulation, int sync_ptr_ioctl)
| Creates a new hw PCM.
int | _snd_pcm_hw_open (snd_pcm_t **pcmp, const char *name, snd_config_t *root, snd_config_t *conf, snd_pcm_stream_t stream, int mode)
| Creates a new hw PCM.

## Detailed Description

PCM HW Plugin Interface.

Author:
  Abramo Bagnara <abramo@alsa-project.org>
  Jaroslav Kysela <perex@perex.cz>

Date:
  2000-2001

## Function Documentation

int _snd_pcm_hw_open | ( | snd_pcm_t ** | pcmp,
|  | const char * | name,
|  | snd_config_t * | root,
|  | snd_config_t * | conf,
|  | snd_pcm_stream_t | stream,
|  | int | mode |
| ) |  |  |

Creates a new hw PCM.

Parameters:

  | pcmp | Returns created PCM handle
  | name | Name of PCM
  | root | Root configuration node
  | conf | Configuration node with hw PCM description
  | stream | PCM Stream
  | mode | PCM Mode

Warning:
  Using of this function might be dangerous in the sense of compatibility reasons. The prototype might be freely changed in future.

int snd_pcm_hw_open | ( | snd_pcm_t ** | pcmp,
|  | const char * | name,
|  | int | card,
|  | int | device,
|  | int | subdevice,
|  | snd_pcm_stream_t | stream,
|  | int | mode,
|  | int | mmap_emulation,
|  | int | sync_ptr_ioctl |
| ) |  |  |

Creates a new hw PCM.

Parameters:

  | pcmp | Returns created PCM handle
  | name | Name of PCM
  | card | Number of card
  | device | Number of device
  | subdevice | Number of subdevice
  | stream | PCM Stream
  | mode | PCM Mode
  | mmap_emulation | Obsoleted parameter
  | sync_ptr_ioctl | Use SYNC_PTR ioctl rather than mmap for control structures

Return values:

  | zero | on success otherwise a negative error code

Warning:
  Using of this function might be dangerous in the sense of compatibility reasons. The prototype might be freely changed in future.

int snd_pcm_hw_open_fd | ( | snd_pcm_t ** | pcmp,
|  | const char * | name,
|  | int | fd,
|  | int | mmap_emulation,
|  | int | sync_ptr_ioctl |
| ) |  |  |

Creates a new hw PCM.

Parameters:

  | pcmp | Returns created PCM handle
  | name | Name of PCM
  | fd | File descriptor
  | mmap_emulation | Obsoleted parameter
  | sync_ptr_ioctl | Boolean flag for sync_ptr ioctl

Return values:

  | zero | on success otherwise a negative error code

Warning:
  Using of this function might be dangerous in the sense of compatibility reasons. The prototype might be freely changed in future.

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