Device discovery: libfprint Reference Manual

## Device discovery Device discovery |

## Functions

struct fp_dscv_dev ** | fp_discover_devs ()
void | fp_dscv_devs_free ()
struct fp_driver * | fp_dscv_dev_get_driver ()
uint32_t | fp_dscv_dev_get_devtype ()
uint16_t | fp_dscv_dev_get_driver_id ()
int | fp_dscv_dev_supports_print_data ()
int | fp_dscv_dev_supports_dscv_print ()
struct fp_dscv_dev * | fp_dscv_dev_for_print_data ()
struct fp_dscv_dev * | fp_dscv_dev_for_dscv_print ()

## Types and Values

struct | fp_dscv_dev

## Includes

    #include <fprint.h>

## Description

These functions allow you to scan the system for supported fingerprint scanning hardware. This is your starting point when integrating libfprint into your software.

When you've identified a discovered device that you would like to control, you can open it with `fp_dev_open()`. Note that discovered devices may no longer be available at the time when you want to open them, for example the user may have unplugged the device.

## Functions

### fp_discover_devs ()

    struct fp_dscv_dev **
    fp_discover_devs (void);

Scans the system and returns a list of discovered devices. This is your entry point into finding a fingerprint reader to operate.

#### Returns

a `NULL`-terminated list of discovered devices. Must be freed with `fp_dscv_devs_free()` after use.

### fp_dscv_devs_free ()

    void
    fp_dscv_devs_free (struct fp_dscv_dev **devs);

Free a list of discovered devices. This function destroys the list and all discovered devices that it included, so make sure you have opened your discovered device before freeing the list.

#### Parameters

devs | the list of discovered devices. If `NULL`, function simply returns. |

### fp_dscv_dev_get_driver ()

    struct fp_driver *
    fp_dscv_dev_get_driver (struct fp_dscv_dev *dev);

Gets the fp_driver for a discovered device.

#### Parameters

dev | the discovered device |

#### Returns

the driver backing the device

### fp_dscv_dev_get_devtype ()

    uint32_t
    fp_dscv_dev_get_devtype (struct fp_dscv_dev *dev);

Gets the devtype for a discovered device.

#### Parameters

dev | the discovered device |

#### Returns

the devtype of the device

### fp_dscv_dev_get_driver_id ()

    uint16_t
    fp_dscv_dev_get_driver_id (struct fp_dscv_dev *dev);

#### Parameters

dev | a discovered fingerprint device |

#### Returns

the ID for the underlying driver for that device

### fp_dscv_dev_supports_print_data ()

    int
    fp_dscv_dev_supports_print_data (struct fp_dscv_dev *dev,
                                     struct fp_print_data *print);

Determines if a specific fp_print_data stored print appears to be compatible with a discovered device.

#### Parameters

dev | the discovered device |
print | the print for compatibility checking |

#### Returns

1 if the print is compatible with the device, 0 otherwise

### fp_dscv_dev_supports_dscv_print ()

    int
    fp_dscv_dev_supports_dscv_print (struct fp_dscv_dev *dev,
                                     struct fp_dscv_print *print);

`fp_dscv_dev_supports_dscv_print` is deprecated and should not be used in newly-written code.

Do not use.

Determines if a specific fp_dscv_print discovered print appears to be compatible with a discovered device.

#### Parameters

dev | the discovered device |
print | the discovered print for compatibility checking |

#### Returns

1 if the print is compatible with the device, 0 otherwise

### fp_dscv_dev_for_print_data ()

    struct fp_dscv_dev *
    fp_dscv_dev_for_print_data (struct fp_dscv_dev **devs,
                                struct fp_print_data *print);

`fp_dscv_dev_for_print_data` is deprecated and should not be used in newly-written code.

Do not use.

Searches a list of discovered devices for a device that appears to be compatible with a fp_print_data stored print.

#### Parameters

devs | a list of discovered devices |
print | the print under inspection |

#### Returns

the first discovered device that appears to support the print, or `NULL` if no apparently compatible devices could be found

### fp_dscv_dev_for_dscv_print ()

    struct fp_dscv_dev *
    fp_dscv_dev_for_dscv_print (struct fp_dscv_dev **devs,
                                struct fp_dscv_print *print);

`fp_dscv_dev_for_dscv_print` is deprecated and should not be used in newly-written code.

Do not use.

Searches a list of discovered devices for a device that appears to be compatible with a fp_dscv_print discovered print.

#### Parameters

devs | a list of discovered devices |
print | the print under inspection |

#### Returns

the first discovered device that appears to support the print, or `NULL` if no apparently compatible devices could be found

## Types and Values

### struct fp_dscv_dev

    struct fp_dscv_dev;

fp_dscv_dev is an opaque structure type. You must access it using the functions below.