comedi_get_subdevice_flags
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## Name

comedi_get_subdevice_flags — properties of subdevice

## Synopsis

    #include <comedilib.h>

`int comedi_get_subdevice_flags(` | comedi_t * device,
| unsigned int subdevice`)`;

## Description

The function `comedi_get_subdevice_flags` returns a bitfield describing the capabilities of the specified subdevice `subdevice` of the Comedi device `device`. If there is an error, `-1` is returned, and the Comedilib error value is set.

Subdevice Flag | Value (hex) | Description
--- | --- | ---

`SDF_BUSY`

`0x00000001`

The subdevice is busy performing an asynchronous command. A subdevice being “busy” is slightly different from the “running” state flagged by `SDF_RUNNING`. A “running” subdevice is always “busy”, but a “busy” subdevice is not necessarily “running”. For example, suppose an analog input command has been completed by the hardware, but there are still samples in Comedi's buffer waiting to be read out. In this case, the subdevice is not “running”, but is still “busy” until all the samples are read out or `comedi_cancel` is called.

`SDF_BUSY_OWNER` | `0x00000002` | The subdevice is “busy”, and the command it is running was started by the current process.
`SDF_LOCKED` | `0x00000004` | The subdevice has been locked by `comedi_lock`.
`SDF_LOCK_OWNER` | `0x00000008` | The subdevice is locked, and was locked by the current process.
`SDF_MAXDATA` | `0x00000010` | The maximum data value for the subdevice depends on the channel.
`SDF_FLAGS` | `0x00000020` | The subdevice flags depend on the channel (unfinished/broken support in library).
`SDF_RANGETYPE` | `0x00000040` | The range type depends on the channel.
`SDF_CMD` | `0x00001000` | The subdevice supports asynchronous commands.
`SDF_SOFT_CALIBRATED` | `0x00002000` | The subdevice relies on the host to do calibration in software. Software calibration coefficients are determined by the comedi_soft_calibrate utility. See the description of the `comedi_get_softcal_converter` function for more information.
`SDF_READABLE` | `0x00010000` | The subdevice can be read (e.g. analog input).
`SDF_WRITABLE` | `0x00020000` | The subdevice can be written to (e.g. analog output).
`SDF_INTERNAL` | `0x00040000` | The subdevice does not have externally visible lines.
`SDF_GROUND` | `0x00100000` | The subdevice supports analog reference `AREF_GROUND`.
`SDF_COMMON` | `0x00200000` | The subdevice supports analog reference `AREF_COMMON`.
`SDF_DIFF` | `0x00400000` | The subdevice supports analog reference `AREF_DIFF`.
`SDF_OTHER` | `0x00800000` | The subdevice supports analog reference `AREF_OTHER`
`SDF_DITHER` | `0x01000000` | The subdevice supports dithering (via the `CR_ALT_FILTER` chanspec flag).
`SDF_DEGLITCH` | `0x02000000` | The subdevice supports deglitching (via the `CR_ALT_FILTER` chanspec flag).
`SDF_RUNNING` | `0x08000000` | An asynchronous command is running. You can use this flag to poll for the completion of an output command.
`SDF_LSAMPL` | `0x10000000` | The subdevice uses the 32-bit lsampl_t type instead of the 16-bit sampl_t for asynchronous command data.
`SDF_PACKED` | `0x20000000` | The subdevice uses bitfield samples for asynchronous command data, one bit per channel (otherwise it uses one sampl_t or lsampl_t per channel). Commonly used for digital subdevices.

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